Multi-layer, elastic articles

ABSTRACT

The invention is an article comprising at least two layers, a low crystallinity layer and a high crystallinity layer. One or both layers is capable of being elongated so that a pre-stretched article is capable of being formed.

FIELD OF THE INVENTION

This invention relates to polymer articles such as laminates, films,fabrics and fibers comprising a low crystallinity layer and a highcrystallinity layer.

BACKGROUND AND SUMMARY OF THE INVENTION

Known co-extrusion processes involve melting of at least two separatepolymer compositions and their simultaneous extrusion and immediatecombination. The extrudate can be cooled, e.g., using a chilled roll,until the polymers have solidified and can be mechanically wound onto aroll. The extrudate may be oriented to a controlled degree in themachine and/or transverse direction. This drawing may be performed attemperatures below the melting point of the co-extrudate. In this way,articles can be made combining the desired properties of differentpolymer compositions.

Co-extruded films are generally made from polymer compositions, whichdevelop considerable mechanical strength upon cooling by the forming ofcrystalline phases. Such polymer compositions are also capable ofdeveloping increased strength upon orientation of the compositions andbetter alignment of the crystalline regions.

Elasticity in films and laminates is desired for a number ofapplications. Examples of such applications are in personal careproducts, such as diaper back sheets, diaper waistbands, and diaperears; medical applications, such as gowns and bags; and garmentapplications, such as disposable wear. In use in the final structure,elastic articles can provide desirable characteristics, such as helpingto achieve compliance of garments to an underlying shape. In diaperwaistbands, for example, a high elastic recovery ensures goodconformability throughout the use of the diaper.

Difficulty in processing elastic monolayer films arises from thetackiness of the films on the roll, which causes “blocking”, i.e.,sticking of the film to itself. This limits the storage of the articleafter it has been produced. Elastic polymers can also have pooraesthetics, including, for example, poor surface appearance and arubbery or tacky feel or touch.

Several approaches have been taken to alleviate these problems. U.S.Pat. No. 6,649,548 discloses laminates of nonwoven fabrics with films toimpart a better feel. U.S. Pat. Nos. 4,629,643 and 5,814,413 and PCTPublications WO 99/47339 and WO 01/05574 disclose various mechanical andprocessing techniques used to emboss or texture the film surface inorder to increase the surface area and improve the feel. U.S. Pat. Nos.4,714,735 and 4,820,590 disclose films comprising an elastomer, ethylenevinyl acetate (EVA), and process oil that are prepared by orienting thefilm at elevated temperature and annealing the film to freeze in thestresses. The film is subsequently heated, which shrinks and forms anelastic film.

In one embodiment, these references also disclose films having layers ofethylene polymers or copolymers on either side of the elastic film toreduce tackiness. By heat-setting the film, it can be stabilized in itsextended condition. Upon application of heat higher than the heatsetting temperature, the heat set is removed and the film returns to itsoriginal length and remains elastic. Two heating steps are involved,adding cost and complexity. U.S. Pat. No. 4,880,682 discloses amultilayer film comprising an elastomer core layer and thermoplasticskin layer(s). The elastomers are ethylene/propylene (EP) rubbers,ethylene/propylene/diene monomer rubbers (EPDM), and butyl rubber, in alaminated structure with EVA as the skin layers. After casting, thesefilms are oriented to yield films having a micro-undulated surfaceproviding a low gloss film.

Micro-textured elastomeric laminated films having at least one adhesivelayer are disclosed in U.S. Pat. Nos. 5,354,597 and 5,376,430. U.S. Pat.No. 4,476,180 describes blends of styrenic block copolymer basedelastomers with ethylene-vinyl acetate copolymers to reduce thetackiness without excessively degrading the mechanical properties.

WO 2004/063270 describes an article that includes a low crystallinitylayer and high crystallinity layer capable of undergoing plasticdeformation upon elongation. The crystallinity layer includes a lowcrystallinity polymer and, optionally, an additional polymer. The highcrystallinity layer includes a high crystallinity polymer having amelting point at least 25 C higher that that of the low crystallinitypolymer. The low crystallinity polymer and the high crystallinitypolymer can have compatible crystallinity.

SUMMARY OF THE INVENTION

In one embodiment the present invention is an article comprising atleast two layers, a first or low crystallinity layer often comprising alow crystallinity polymer and a second or high crystallinity layer oftencomprising a high crystallinity polymer. The high crystallinity polymermay have a melting point as determined by differential scanningcalorimetry (DSC) that is about the same, greater than, or less than, orwithin about 25 C of the melting point of the low crystallinity polymer.The article is capable of being elongated at a temperature below themelting point of the lowest melting component in at least one directionto an elongation of at least about 50%, preferably at least about 100%and more preferably at least about 150%, of its original length orwidth, to form a pre-stretched, and optionally subsequently relaxed,article. Preferably, the high crystallinity layer is capable ofundergoing plastic deformation upon the elongation.

In another embodiment, the invention is a pre-stretched, multi-layerfilm or laminate comprising:

A. At least one core or non-skin layer comprising (i) opposing first andsecond planar surfaces, and (ii) a low crystalline, elastic polymer, and

B. At least one first and, optionally a second, outer or skin layer(s)each comprising (i) opposing first and second planar surfaces, and (ii)a high crystalline polymer, the second or bottom planar surface of thefirst outer layer in intimate contact with the first or top planarsurface of the core layer and the first or top planar surface of thesecond outer layer in intimate contact with the bottom or second planarsurface of the core layer. The high crystalline polymer of one skinlayer can be the same or different than the high crystalline polymer ofthe other skin layer. Preferably the at least one core layer polymer isan ethylene/α-olefin multi-block interpolymer component that are furtherdefined and discussed in copending PCT Application No.PCT/US2005/008917, filed on Mar. 17, 2005 and published on Sep. 29, 2005as WO/2005/090427, and the at least one skin layer polymer is typicallya polyolefin. Typically, the skin layer polymer of the first and secondouter layers is often the same.

Upon preparation, the articles of the present invention may be stretchedor activated, typically at an elongation of at least about 50%,preferably at least about 100% and more preferably at least about 150%,more preferably at least 300%, more preferably at least 400% of itsoriginal measurement (e.g. length or width) to an approximate maximum of500% to 1500%. The stretched article is optionally subsequently relaxedto a very low tension to allow substantial elastic recovery beforewinding up on a roll.

In another embodiment, the invention is a process for making apre-stretched, multi-layer film comprising at least two layers, a firstor low crystallinity layer comprising a low crystallinity polymer and asecond or high crystallinity layer comprising a high crystallinitypolymer. The process comprises the steps of: (1) forming the film, and(2) elongating the film in at least one direction to at least about150%, preferably at least about 200%, of its original length or width.Preferably, the film is elongated at a temperature below the meltingpoint of the high crystallinity polymer, more preferably at atemperature below the melting point of the low crystallinity polymer.The elongation step produces a film with a haze value of greater than0%, typically of at least 10%, more typically of at least 25%, and evenmore typically of at least 50%.

In another embodiment, the invention is the article described in thefirst and second embodiments in the form of a fiber, preferably abicomponent fiber. Preferably, the high crystallinity polymer comprisesat least a portion of the surface of the fiber, especially in fiberswith a configuration of sheath/core, side-by-side, crescent moon,tri-lobal, islands-in-the-sea, or flat, although there are someapplications where the low crystallinity polymer can comprise at least aportion of the surface of the fiber, e.g., binder fiber applications.Fibers in which the high crystallinity polymer has been plasticallydeformed are particularly preferred.

Other embodiments of the invention include the article described in theprevious embodiments in the form of a woven, nonwoven or woven/nonwovenblended fabric, films comprising four or more layers, garments and otherstructures made from the articles, e.g., diaper back-sheets and elastictabs, hospital wear, etc., cross-linked articles, articles containingfillers and the like. Another preferred embodiment is an articledescribed in the previous embodiments comprising a laminate comprisingnonwoven/film/nonwoven laminates, nonwoven/nonwoven/nonwoven laminates,laminates comprising at least two nonwovens, and woven/nonwovenlaminates.

In many embodiments of this invention, preferably the weight percentcrystallinity difference between the high and low crystallinity layersis at least about 3%, preferably at least about 5% and more preferablyat least about 10% and not in excess of about 90%.

In many embodiments, the article may comprise at least oneethylene/α-olefin interpolymer in the low crystallinity layer, the highcrystallinity layer, either, or both, wherein the ethylene/α-olefininterpolymer is described in and discussed in copending PCT ApplicationNo. PCT/US2005/008917, filed on Mar. 17, 2005 and published on Sep. 29,2005 as WO/2005/090427 which is incorporated herein by reference. Theethylene/α-olefin interpolymer is characterized by one or more of thefollowing:

(a) has a Mw/Mn from about 1.7 to about 3.5, at least one melting point,Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter,wherein the numerical values of Tm and d correspond to the relationship:

T _(m)≧858.91−1825.3(d)+1112.8(d)²; or

(b) has a Mw/Mn from about 1.7 to about 3.5, and is characterized by aheat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsiusdefined as the temperature difference between the tallest DSC peak andthe tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH havethe following relationships:

ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,

ΔT≧48° C. for ΔH greater than 130 J/g,

wherein the CRYSTAF peak is determined using at least 5 percent of thecumulative polymer, and if less than 5 percent of the polymer has anidentifiable CRYSTAF peak, then the CRYSTAF temperature is 30° C.; or

(c) is characterized by an elastic recovery, Re, in percent at 300percent strain and 1 cycle measured with a compression-molded film ofthe ethylene/α-olefin interpolymer, and has a density, d, in grams/cubiccentimeter, wherein the numerical values of Re and d satisfy thefollowing relationship when ethylene/α-olefin interpolymer issubstantially free of a cross-linked phase:

Re>1481−1629(d); or

(d) has a molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has amolar comonomer content of at least 5 percent higher than that of acomparable random ethylene interpolymer fraction eluting between thesame temperatures, wherein said comparable random ethylene interpolymerhas the same comonomer(s) and has a melt index, density, and molarcomonomer content (based on the whole polymer) within 10 percent of thatof the ethylene/α-olefin interpolymer; or

(e) has a storage modulus at 25° C., G′(25° C.), and a storage modulusat 100° C., G′(100° C.), wherein the ratio of G′(25° C.) to G′(100° C.)is in the range of about 1:1 to about 9:1

wherein the ethylene/α-olefin interpolymer has a density of from about0.85 to about 0.89 g/cc and a melt index (12) of from about 0.5 g/10min. to about 20 g/10 min.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the melting point/density relationship for the inventivepolymers (represented by diamonds) as compared to traditional randomcopolymers (represented by circles) and Ziegler-Natta copolymers(represented by triangles).

FIG. 2 shows plots of delta DSC-CRYSTAF as a function of DSC MeltEnthalpy for various polymers. The diamonds represent randomethylene/octene copolymers; the squares represent polymer examples 1-4;the triangles represent polymer examples 5-9; and the circles representpolymer examples 10-19. The “X” symbols represent polymer examplesA*-F*.

FIG. 3 shows the effect of density on elastic recovery for unorientedfilms made from inventive interpolymers (represented by the squares andcircles) and traditional copolymers (represented by the triangles whichare various Dow AFFINITY® polymers). The squares represent inventiveethylene/butene copolymers; and the circles represent inventiveethylene/octene copolymers.

FIG. 4 is a plot of octene content of TREF fractionatedethylene/1-octene copolymer fractions versus TREF elution temperature ofthe fraction for the polymer of Example 5 (represented by the circles)and comparative polymers E and F (represented by the “X” symbols). Thediamonds represent traditional random ethylene/octene copolymers.

FIG. 5 is a plot of octene content of TREF fractionatedethylene/1-octene copolymer fractions versus TREF elution temperature ofthe fraction for the polymer of Example 5 (curve 1) and for comparativeF (curve 2). The squares represent Example F*; and the trianglesrepresent Example 5.

FIG. 6 is a graph of the log of storage modulus as a function oftemperature for comparative ethylene/1-octene copolymer (curve 2) andpropylene/ethylene-copolymer (curve 3) and for two ethylene/1-octeneblock copolymers of the invention made with differing quantities ofchain shuttling agent (curves 1).

FIG. 7 shows a plot of TMA (1 mm) versus flex modulus for some inventivepolymers (represented by the diamonds), as compared to some knownpolymers. The triangles represent various Dow VERSIFY® polymers; thecircles represent various random ethylene/styrene copolymers; and thesquares represent various Dow AFFINITY® polymers.

DETAILED DESCRIPTION OF THE INVENTION

“Low crystallinity”, “high crystallinity” and like terms are used in arelative sense, not in an absolute sense. However, low crystallinitylayers have crystallinity of from about 1 to about 25, preferably fromabout 1 to about 20, and more preferably from about 1 to about 15 weightpercent crystallinity.

Typical high crystalline polymers often include linear low densitypolyethylene (LLDPE), low density polyethylene (LDPE), LLDPE/LDPEblends, high density polyethylene (HDPE), homopolypropylene (hPP),substantially linear ethylene polymer (SLEP), random propylene basedcopolymer, polypropylene (PP) plastomers and elastomers, randomcopolymer (RCP), and the like, and various blends thereof. Lowcrystallinity polymers of particular interest preferably includeethylene/α-olefin multi-block interpolymers defined and discussed incopending PCT Application No. PCT/US2005/008917, filed on Mar. 17, 2005and published on Sep. 29, 2005 as WO/2005/090427, which in turn claimspriority to U.S. Provisional Application No. 60/553,906, filed Mar. 17,2004, both which are incorporated by reference. Low crystalline polymersalso include propylene/ethylene, propylene/1-butene, propylene/1-hexene,propylene/4-methyl-1-pentene, propylene/1-octene,propylene/ethylene/1-butene, propylene/ethylene/ENB,propylene/ethylene/1-hexene, propylene/ethylene/1-octene,propylene/styrene, and propylene/ethylene/styrene. Representative ofthese copolymers are the VERSIFY® elastic propylene copolymersmanufactured and marketed by The Dow Chemical Company and VISTAMAXXpropylene copolymers made by Exxon-Mobil.

The term “polymer” generally includes, but is not limited to,homopolymers, copolymers, such as, for example, block, graft, random andalternating copolymers, terpolymers, etc., and blends and modificationsof the same. Furthermore, unless otherwise specifically limited, theterm “polymer” shall include all possible geometrical configurations ofthe material. These configurations include, but are not limited to,isotactic, syndiotactic and random symmetries.

All percentages specified herein are weight percentages unless otherwisespecified.

“Interpolymer” means a polymer prepared by the polymerization of atleast two different types of monomers. The generic term “interpolymer”includes the term “copolymer” (which is usually employed to refer to apolymer prepared from two different monomers) as well as the term“terpolymer” (which is usually employed to refer to a polymer preparedfrom three different types of monomers). It also encompasses polymersmade by polymerizing four or more types of monomers.

The term “ethylene/α-olefin interpolymer” generally refers to polymerscomprising ethylene and an α-olefin having 3 or more carbon atoms.Preferably, ethylene comprises the majority mole fraction of the wholepolymer, i.e., ethylene comprises at least about 50 mole percent of thewhole polymer. More preferably ethylene comprises at least about 60 molepercent, at least about 70 mole percent, or at least about 80 molepercent, with the substantial remainder of the whole polymer comprisingat least one other comonomer that is preferably an α-olefin having 3 ormore carbon atoms. For many ethylene/octene copolymers, the preferredcomposition comprises an ethylene content greater than about 80 molepercent of the whole polymer and an octene content of from about 10 toabout 15, preferably from about 15 to about 20 mole percent of the wholepolymer. In some embodiments, the ethylene/α-olefin interpolymers do notinclude those produced in low yields or in a minor amount or as aby-product of a chemical process. While the ethylene/α-olefininterpolymers can be blended with one or more polymers, the as-producedethylene/α-olefin interpolymers are substantially pure and oftencomprise a major component of the reaction product of a polymerizationprocess.

The ethylene/α-olefin interpolymers comprise ethylene and one or morecopolymerizable α-olefin comonomers in polymerized form, characterizedby multiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties. That is, theethylene/α-olefin interpolymers are block interpolymers, preferablymulti-block interpolymers or copolymers. The terms “interpolymer” andcopolymer” are used interchangeably herein. In some embodiments, themulti-block copolymer can be represented by the following formula:

(AB)n

where n is at least 1, preferably an integer greater than 1, such as 2,3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A”represents a hard block or segment and “B” represents a soft block orsegment. Preferably, As and Bs are linked in a substantially linearfashion, as opposed to a substantially branched or substantiallystar-shaped fashion. In other embodiments, A blocks and B blocks arerandomly distributed along the polymer chain. In other words, the blockcopolymers usually do not have a structure as follows.

AAA-AA-BBB-BB

In still other embodiments, the block copolymers do not usually have athird type of block, which comprises different comonomer(s). In yetother embodiments, each of block A and block B has monomers orcomonomers substantially randomly distributed within the block. In otherwords, neither block A nor block B comprises two or more sub-segments(or sub-blocks) of distinct composition, such as a tip segment, whichhas a substantially different composition than the rest of the block.

The multi-block polymers typically comprise various amounts of “hard”and “soft” segments. “Hard” segments refer to blocks of polymerizedunits in which ethylene is present in an amount greater than about 95weight percent, and preferably greater than about 98 weight percentbased on the weight of the polymer. In other words, the comonomercontent (content of monomers other than ethylene) in the hard segmentsis less than about 5 weight percent, and preferably less than about 2weight percent based on the weight of the polymer. In some embodiments,the hard segments comprises all or substantially all ethylene. “Soft”segments, on the other hand, refer to blocks of polymerized units inwhich the comonomer content (content of monomers other than ethylene) isgreater than about 5 weight percent, preferably greater than about 8weight percent, greater than about 10 weight percent, or greater thanabout 15 weight percent based on the weight of the polymer. In someembodiments, the comonomer content in the soft segments can be greaterthan about 20 weight percent, greater than about 25 weight percent,greater than about 30 weight percent, greater than about 35 weightpercent, greater than about 40 weight percent, greater than about 45weight percent, greater than about 50 weight percent, or greater thanabout 60 weight percent.

The soft segments can often be present in a block interpolymer fromabout 1 weight percent to about 99 weight percent of the total weight ofthe block interpolymer, preferably from about 5 weight percent to about95 weight percent, from about 10 weight percent to about 90 weightpercent, from about 15 weight percent to about 85 weight percent, fromabout 20 weight percent to about 80 weight percent, from about 25 weightpercent to about 75 weight percent, from about 30 weight percent toabout 70 weight percent, from about 35 weight percent to about 65 weightpercent, from about 40 weight percent to about 60 weight percent, orfrom about 45 weight percent to about 55 weight percent of the totalweight of the block interpolymer. Conversely, the hard segments can bepresent in similar ranges. The soft segment weight percentage and thehard segment weight percentage can be calculated based on data obtainedfrom DSC or NMR. Such methods and calculations are disclosed in aconcurrently filed U.S. patent application Ser. No. 11/376,835, AttorneyDocket No. 385063-999558, entitled “Ethylene/α-Olefin BlockInterpolymers”, filed on Mar. 15, 2006, in the name of Colin L. P. Shan,Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc.,the disclosure of which is incorporated by reference herein in itsentirety.

Ethylene/α-Olefin Interpolymers

The ethylene/α-olefin interpolymers used in embodiments of the invention(also referred to as “inventive interpolymer” or “inventive polymer”)comprise ethylene and one or more copolymerizable α-olefin comonomers inpolymerized form, characterized by multiple blocks or segments of two ormore polymerized monomer units differing in chemical or physicalproperties (block interpolymer), preferably a multi-block copolymer. Theethylene/α-olefin interpolymers are characterized by one or more of theaspects described as follows.

In one aspect, the ethylene/α-olefin interpolymers used in embodimentsof the invention have a M_(w)/M_(n) from about 1.7 to about 3.5 and atleast one melting point, T_(m), in degrees Celsius and density, d, ingrams/cubic centimeter, wherein the numerical values of the variablescorrespond to the relationship:

T _(m)>−2002.9+4538.5(d)−2422.2(d)², and preferably

T _(m)≧−6288.1+13141(d)−6720.3(d)², and more preferably

T _(m)≧858.91−1825.3(d)+1112.8(d)².

Such melting point/density relationship is illustrated in FIG. 1. Unlikethe traditional random copolymers of ethylene/α-olefins whose meltingpoints decrease with decreasing densities, the inventive interpolymers(represented by diamonds) exhibit melting points substantiallyindependent of the density, particularly when density is between about0.87 g/cc to about 0.95 g/cc. For example, the melting point of suchpolymers are in the range of about 110° C. to about 130° C. when densityranges from 0.875 g/cc to about 0.945 g/cc. In some embodiments, themelting point of such polymers are in the range of about 115° C. toabout 125° C. when density ranges from 0.875 g/cc to about 0.945 g/cc.

In another aspect, the ethylene/α-olefin interpolymers comprise, inpolymerized form, ethylene and one or more α-olefins and arecharacterized by a ΔT, in degree Celsius, defined as the temperature forthe tallest Differential Scanning Calorimetry (“DSC”) peak minus thetemperature for the tallest Crystallization Analysis Fractionation(“CRYSTAF”) peak and a heat of fusion in J/g, ΔH, and ΔT and ΔH satisfythe following relationships:

ΔT>−0.1299(ΔH)+62.81, and preferably

ΔT≧−0.1299(ΔH)+64.38, and more preferably

ΔT≧−0.1299(ΔH)+65.95,

for ΔH up to 130 J/g. Moreover, ΔT is equal to or greater than 48° C.for ΔH greater than 130 J/g. The CRYSTAF peak is determined using atleast 5 percent of the cumulative polymer (that is, the peak mustrepresent at least 5 percent of the cumulative polymer), and if lessthan 5 percent of the polymer has an identifiable CRYSTAF peak, then theCRYSTAF temperature is 30° C., and ΔH is the numerical value of the heatof fusion in J/g. More preferably, the highest CRYSTAF peak contains atleast 10 percent of the cumulative polymer. FIG. 2 shows plotted datafor inventive polymers as well as comparative examples. Integrated peakareas and peak temperatures are calculated by the computerized drawingprogram supplied by the instrument maker. The diagonal line shown forthe random ethylene octene comparative polymers corresponds to theequation ΔT=−0.1299 (ΔH)+62.81.

In yet another aspect, the ethylene/α-olefin interpolymers have amolecular fraction which elutes between 40° C. and 130° C. whenfractionated using Temperature Rising Elution Fractionation (“TREF”),characterized in that said fraction has a molar comonomer contenthigher, preferably at least 5 percent higher, more preferably at least10 percent higher, than that of a comparable random ethyleneinterpolymer fraction eluting between the same temperatures, wherein thecomparable random ethylene interpolymer contains the same comonomer(s),and has a melt index, density, and molar comonomer content (based on thewhole polymer) within 10 percent of that of the block interpolymer.Preferably, the Mw/Mn of the comparable interpolymer is also within 10percent of that of the block interpolymer and/or the comparableinterpolymer has a total comonomer content within 10 weight percent ofthat of the block interpolymer.

In still another aspect, the ethylene/α-olefin interpolymers arecharacterized by an elastic recovery, Re, in percent at 300 percentstrain and 1 cycle measured on a compression-molded film of anethylene/α-olefin interpolymer, and has a density, d, in grams/cubiccentimeter, wherein the numerical values of Re and d satisfy thefollowing relationship when ethylene/α-olefin interpolymer issubstantially free of a cross-linked phase:

Re>1481−1629(d); and preferably

Re≧1491−1629(d); and more preferably

Re≧1501−1629(d); and even more preferably

Re≧1511−1629(d).

FIG. 3 shows the effect of density on elastic recovery for unorientedfilms made from certain inventive interpolymers and traditional randomcopolymers. For the same density, the inventive interpolymers havesubstantially higher elastic recoveries.

In some embodiments, the ethylene/α-olefin interpolymers have a tensilestrength above 10 MPa, preferably a tensile strength≧11 MPa, morepreferably a tensile strength≧13 MPa and/or an elongation at break of atleast 600 percent, more preferably at least 700 percent, highlypreferably at least 800 percent, and most highly preferably at least 900percent at a crosshead separation rate of 11 cm/minute.

In other embodiments, the ethylene/α-olefin interpolymers have (1) astorage modulus ratio, G′(25° C.)/G′(100° C.), of from 1 to 50,preferably from 1 to 20, more preferably from 1 to 10; and/or (2) a 70°C. compression set of less than 80 percent, preferably less than 70percent, especially less than 60 percent, less than 50 percent, or lessthan 40 percent, down to a compression set of 0 percent.

In still other embodiments, the ethylene/α-olefin interpolymers have a70° C. compression set of less than 80 percent, less than 70 percent,less than 60 percent, or less than 50 percent. Preferably, the 70° C.compression set of the interpolymers is less than 40 percent, less than30 percent, less than 20 percent, and may go down to about 0 percent.

In some embodiments, the ethylene/α-olefin interpolymers have a heat offusion of less than 85 J/g and/or a pellet blocking strength of equal toor less than 100 pounds/foot² (4800 Pa), preferably equal to or lessthan 50 lbs/ft² (2400 Pa), especially equal to or less than 5 lbs/ft²(240 Pa), and as low as 0 lbs/ft² (0 Pa).

In other embodiments, the ethylene/α-olefin interpolymers comprise, inpolymerized form, at least 50 mole percent ethylene and have a 70° C.compression set of less than 80 percent, preferably less than 70 percentor less than 60 percent, most preferably less than 40 to 50 percent anddown to close zero percent.

In some embodiments, the multi-block copolymers possess a PDI fitting aSchultz-Flory distribution rather than a Poisson distribution. Thecopolymers are further characterized as having both a polydisperse blockdistribution and a polydisperse distribution of block sizes andpossessing a most probable distribution of block lengths. Preferredmulti-block copolymers are those containing 4 or more blocks or segmentsincluding terminal blocks. More preferably, the copolymers include atleast 5, 10 or 20 blocks or segments including terminal blocks.

Comonomer content may be measured using any suitable technique, withtechniques based on nuclear magnetic resonance (“NMR”) spectroscopypreferred. Moreover, for polymers or blends of polymers havingrelatively broad TREF curves, the polymer desirably is firstfractionated using TREF into fractions each having an eluted temperaturerange of 10° C. or less. That is, each eluted fraction has a collectiontemperature window of 10° C. or less. Using this technique, said blockinterpolymers have at least one such fraction having a higher molarcomonomer content than a corresponding fraction of the comparableinterpolymer.

In another aspect, the inventive polymer is an olefin interpolymer,preferably comprising ethylene and one or more copolymerizablecomonomers in polymerized form, characterized by multiple blocks (i.e.,at least two blocks) or segments of two or more polymerized monomerunits differing in chemical or physical properties (blockedinterpolymer), most preferably a multi-block copolymer, said blockinterpolymer having a peak (but not just a molecular fraction) whichelutes between 40° C. and 130° C. (but without collecting and/orisolating individual fractions), characterized in that said peak, has acomonomer content estimated by infra-red spectroscopy when expandedusing a full width/half maximum (FWHM) area calculation, has an averagemolar comonomer content higher, preferably at least 5 percent higher,more preferably at least 10 percent higher, than that of a comparablerandom ethylene interpolymer peak at the same elution temperature andexpanded using a full width/half maximum (FWHM) area calculation,wherein said comparable random ethylene interpolymer has the samecomonomer(s) and has a melt index, density, and molar comonomer content(based on the whole polymer) within 10 percent of that of the blockedinterpolymer. Preferably, the Mw/Mn of the comparable interpolymer isalso within 10 percent of that of the blocked interpolymer and/or thecomparable interpolymer has a total comonomer content within 10 weightpercent of that of the blocked interpolymer. The full width/half maximum(FWHM) calculation is based on the ratio of methyl to methylene responsearea [CH₃/CH₂] from the ATREF infra-red detector, wherein the tallest(highest) peak is identified from the base line, and then the FWHM areais determined. For a distribution measured using an ATREF peak, the FWHMarea is defined as the area under the curve between T₁ and T₂, where T₁and T₂ are points determined, to the left and right of the ATREF peak,by dividing the peak height by two, and then drawing a line horizontalto the base line, that intersects the left and right portions of theATREF curve. A calibration curve for comonomer content is made usingrandom ethylene/α-olefin copolymers, plotting comonomer content from NMRversus FWHM area ratio of the TREF peak. For this infra-red method, thecalibration curve is generated for the same comonomer type of interest.The comonomer content of TREF peak of the inventive polymer can bedetermined by referencing this calibration curve using its FWHMmethyl:methylene area ratio [CH₃/CH₂] of the TREF peak.

Comonomer content may be measured using any suitable technique, withtechniques based on nuclear magnetic resonance (NMR) spectroscopypreferred. Using this technique, said blocked interpolymers has highermolar comonomer content than a corresponding comparable interpolymer.

Preferably, for interpolymers of ethylene and 1-octene, the blockinterpolymer has a comonomer content of the TREF fraction elatingbetween 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperatureof the TREF fraction being compared, measured in ° C.

FIG. 4 graphically depicts an embodiment of the block interpolymers ofethylene and 1-octene where a plot of the comonomer content versus TREFelution temperature for several comparable ethylene/1-octeneinterpolymers (random copolymers) are fit to a line representing(−0.2013) T+20.07 (solid line). The line for the equation (−0.2013)T+21.07 is depicted by a dotted line. Also depicted are the comonomercontents for fractions of several block ethylene/1-octene interpolymersof the invention (multi-block copolymers). All of the block interpolymerfractions have significantly higher 1-octene content than either line atequivalent elution temperatures. This result is characteristic of theinventive interpolymer and is believed to be due to the presence ofdifferentiated blocks within the polymer chains, having both crystallineand amorphous nature.

FIG. 5 graphically displays the TREF curve and comonomer contents ofpolymer fractions for Example 5 and comparative F to be discussed below.The peak eluting from 40 to 130° C., preferably from 60° C. to 95° C.for both polymers is fractionated into three parts, each part elutingover a temperature range of less than 10° C. Actual data for Example 5is represented by triangles. The skilled artisan can appreciate that anappropriate calibration curve may be constructed for interpolymerscontaining different comonomers and a line used as a comparison fittedto the TREF values obtained from comparative interpolymers of the samemonomers, preferably random copolymers made using a metallocene or otherhomogeneous catalyst composition. Inventive interpolymers arecharacterized by a molar comonomer content greater than the valuedetermined from the calibration curve at the same TREF elutiontemperature, preferably at least 5 percent greater, more preferably atleast 10 percent greater.

In addition to the above aspects and properties described herein, theinventive polymers can be characterized by one or more additionalcharacteristics. In one aspect, the inventive polymer is an olefininterpolymer, preferably comprising ethylene and one or morecopolymerizable comonomers in polymerized form, characterized bymultiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties (blocked interpolymer),most preferably a multi-block copolymer, said block interpolymer havinga molecular fraction which elutes between 40° C. and 130° C., whenfractionated using TREF increments, characterized in that said fractionhas a molar comonomer content higher, preferably at least 5 percenthigher, more preferably at least 10, 15, 20 or 25 percent higher, thanthat of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer comprises the same comonomer(s), preferably it is the samecomonomer(s), and a melt index, density, and molar comonomer content(based on the whole polymer) within 10 percent of that of the blockedinterpolymer. Preferably, the Mw/Mn of the comparable interpolymer isalso within 10 percent of that of the blocked interpolymer and/or thecomparable interpolymer has a total comonomer content within 10 weightpercent of that of the blocked interpolymer.

Preferably, the above interpolymers are interpolymers of ethylene and atleast one α-olefin, especially those interpolymers having a wholepolymer density from about 0.855 to about 0.935 g/cm³, and moreespecially for polymers having more than about 1 mole percent comonomer,the blocked interpolymer has a comonomer content of the TREF fractioneluting between 40 and 130° C. greater than or equal to the quantity(−0.1356) T+13.89, more preferably greater than or equal to the quantity(−0.1356) T+14.93, and most preferably greater than or equal to thequantity (−0.2013)T+21.07, where T is the numerical value of the peakATREF elution temperature of the TREF fraction being compared, measuredin ° C.

Preferably, for the above interpolymers of ethylene and at least onealpha-olefin especially those interpolymers having a whole polymerdensity from about 0.855 to about 0.935 g/cm³, and more especially forpolymers having more than about 1 mole percent comonomer, the blockedinterpolymer has a comonomer content of the TREF fraction elutingbetween 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperatureof the TREF fraction being compared, measured in ° C.

In still another aspect, the inventive polymer is an olefininterpolymer, preferably comprising ethylene and one or morecopolymerizable comonomers in polymerized form, characterized bymultiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties (blocked interpolymer),most preferably a multi-block copolymer, said block interpolymer havinga molecular fraction which elutes between 40° C. and 130° C., whenfractionated using TREF increments, characterized in that every fractionhaving a comonomer content of at least about 6 mole percent, has amelting point greater than about 100° C. For those fractions having acomonomer content from about 3 mole percent to about 6 mole percent,every fraction has a DSC melting point of about 110° C. or higher. Morepreferably, said polymer fractions, having at least 1 mol percentcomonomer, has a DSC melting point that corresponds to the equation:

Tm≧(−5.5926)(mol percent comonomer in the fraction)+135.90.

In yet another aspect, the inventive polymer is an olefin interpolymer,preferably comprising ethylene and one or more copolymerizablecomonomers in polymerized form, characterized by multiple blocks orsegments of two or more polymerized monomer units differing in chemicalor physical properties (blocked interpolymer), most preferably amulti-block copolymer, said block interpolymer having a molecularfraction which elutes between 40° C. and 130° C., when fractionatedusing TREF increments, characterized in that every fraction that has anATREF elution temperature greater than or equal to about 76° C., has amelt enthalpy (heat of fusion) as measured by DSC, corresponding to theequation:

Heat of fusion(J/gm)≦(3.1718)(ATREF elution temperature inCelsius)−136.58,

The inventive block interpolymers have a molecular fraction which elutesbetween 40° C. and 130° C., when fractionated using TREF increments,characterized in that every fraction that has an ATREF elutiontemperature between 40° C. and less than about 76° C., has a meltenthalpy (heat of fusion) as measured by DSC, corresponding to theequation:

Heat of fusion(J/gm)≦(1.1312)(ATREF elution temperature inCelsius)+22.97.

ATREF Peak Comonomer Composition Measurement by Infra-Red Detector

The comonomer composition of the TREF peak can be measured using an IR4infra-red detector available from Polymer Char, Valencia, Spain(http://www.polymerchar.com/).

The “composition mode” of the detector is equipped with a measurementsensor (CH₂) and composition sensor (CH₃) that are fixed narrow bandinfra-red filters in the region of 2800-3000 cm⁻¹. The measurementsensor detects the methylene (CH₂) carbons on the polymer (whichdirectly relates to the polymer concentration in solution) while thecomposition sensor detects the methyl (CH₃) groups of the polymer. Themathematical ratio of the composition signal (CH₃) divided by themeasurement signal (CH₂) is sensitive to the comonomer content of themeasured polymer in solution and its response is calibrated with knownethylene alpha-olefin copolymer standards.

The detector when used with an ATREF instrument provides both aconcentration (CH₂) and composition (CH₃) signal response of the elutedpolymer during the TREF process. A polymer specific calibration can becreated by measuring the area ratio of the CH₃ to CH₂ for polymers withknown comonomer content (preferably measured by NMR). The comonomercontent of an ATREF peak of a polymer can be estimated by applying a thereference calibration of the ratio of the areas for the individual CH₃and CH₂ response (i.e. area ratio CH₃/CH₂ versus comonomer content).

The area of the peaks can be calculated using a full width/half maximum(FWHM) calculation after applying the appropriate baselines to integratethe individual signal responses from the TREF chromatogram. The fullwidth/half maximum calculation is based on the ratio of methyl tomethylene response area [CH₃/CH₂] from the ATREF infra-red detector,wherein the tallest (highest) peak is identified from the base line, andthen the FWHM area is determined. For a distribution measured using anATREF peak, the FWHM area is defined as the area under the curve betweenT1 and T2, where T1 and T2 are points determined, to the left and rightof the ATREF peak, by dividing the peak height by two, and then drawinga line horizontal to the base line, that intersects the left and rightportions of the ATREF curve.

The application of infra-red spectroscopy to measure the comonomercontent of polymers in this ATREF-infra-red method is, in principle,similar to that of GPC/FTIR systems as described in the followingreferences: Markovich, Ronald P.; Hazlitt, Lonnie G.; Smith, Linley;“Development of gel-permeation chromatography-Fourier transform infraredspectroscopy for characterization of ethylene-based polyolefincopolymers”. Polymeric Materials Science and Engineering (1991), 65,98-100.; and Deslauriers, P. J.; Rohlfing, D. C.; Shieh, E. T.;“Quantifying short chain branching microstructures in ethylene-1-olefincopolymers using size exclusion chromatography and Fourier transforminfrared spectroscopy (SEC-FTIR)”, Polymer (2002), 43, 59-170., both ofwhich are incorporated by reference herein in their entirety.

In other embodiments, the inventive ethylene/α-olefin interpolymer ischaracterized by an average block index, ABI, which is greater than zeroand up to about 1.0 and a molecular weight distribution, M_(w)/M_(n),greater than about 1.3. The average block index, ABI, is the weightaverage of the block index (“BI”) for each of the polymer fractionsobtained in preparative TREF from 20° C. and 110° C., with an incrementof 5° C.:

ABI=Σ(w _(i)BI_(i))

where BI_(i) is the block index for the ith fraction of the inventiveethylene/α-olefin interpolymer obtained in preparative TREF, and w_(i)is the weight percentage of the ith fraction.

For each polymer fraction, BI is defined by one of the two followingequations (both of which give the same BI value):

${BI} = {{\frac{{1/T_{X}} - {1/T_{XO}}}{{1/T_{A}} - {1/T_{AB}}}\mspace{14mu} {or}\mspace{14mu} {BI}} = \frac{{LnP}_{X} - {LnP}_{XO}}{{LnP}_{A} - {LnP}_{AB}}}$

where T_(X) is the preparative ATREF elution temperature for the ithfraction (preferably expressed in Kelvin), P_(X) is the ethylene molefraction for the ith fraction, which can be measured by NMR or IR asdescribed above. P_(AB) is the ethylene mole fraction of the wholeethylene/α-olefin interpolymer (before fractionation), which also can bemeasured by NMR or IR. T_(A) and P_(A) are the ATREF elution temperatureand the ethylene mole fraction for pure “hard segments” (which refer tothe crystalline segments of the interpolymer). As a first orderapproximation, the T_(A) and P_(A) values are set to those for highdensity polyethylene homopolymer, if the actual values for the “hardsegments” are not available. For calculations performed herein, T_(A) is372° K., P_(A) is 1.

T_(AB) is the ATREF temperature for a random copolymer of the samecomposition and having an ethylene mole fraction of P_(AB). T_(AB) canbe calculated from the following equation:

Ln P _(AB)=α/T_(AB)+β

where α and β are two constants which can be determined by calibrationusing a number of known random ethylene copolymers. It should be notedthat α and β may vary from instrument to instrument. Moreover, one wouldneed to create their own calibration curve with the polymer compositionof interest and also in a similar molecular weight range as thefractions. There is a slight molecular weight effect. If the calibrationcurve is obtained from similar molecular weight ranges, such effectwould be essentially negligible. In some embodiments, random ethylenecopolymers satisfy the following relationship:

Ln P=−237.83/T _(ATREF)+0.639

T_(XO) is the ATREF temperature for a random copolymer of the samecomposition and having an ethylene mole fraction of P_(X). T_(XO) can becalculated from Ln P_(X)=α/T_(XO)+β. Conversely, P_(XO) is the ethylenemole fraction for a random copolymer of the same composition and havingan ATREF temperature of T_(X), which can be calculated from LnP_(XO)=α/T_(X)+β.

Once the block index (BI) for each preparative TREF fraction isobtained, the weight average block index, ABI, for the whole polymer canbe calculated. In some embodiments, ABI is greater than zero but lessthan about 0.3 or from about 0.1 to about 0.3. In other embodiments, ABIis greater than about 0.3 and up to about 1.0. Preferably, ABI should bein the range of from about 0.4 to about 0.7, from about 0.5 to about0.7, or from about 0.6 to about 0.9. In some embodiments, ABI is in therange of from about 0.3 to about 0.9, from about 0.3 to about 0.8, orfrom about 0.3 to about 0.7, from about 0.3 to about 0.6, from about 0.3to about 0.5, or from about 0.3 to about 0.4. In other embodiments, ABIis in the range of from about 0.4 to about 1.0, from about 0.5 to about1.0, or from about 0.6 to about 1.0, from about 0.7 to about 1.0, fromabout 0.8 to about 1.0, or from about 0.9 to about 1.0.

Another characteristic of the inventive ethylene/α-olefin interpolymeris that the inventive ethylene/α-olefin interpolymer comprises at leastone polymer fraction which can be obtained by preparative TREF, whereinthe fraction has a block index greater than about 0.1 and up to about1.0 and a molecular weight distribution, M_(w)/M_(n), greater than about1.3. In some embodiments, the polymer fraction has a block index greaterthan about 0.6 and up to about 1.0, greater than about 0.7 and up toabout 1.0, greater than about 0.8 and up to about 1.0, or greater thanabout 0.9 and up to about 1.0. In other embodiments, the polymerfraction has a block index greater than about 0.1 and up to about 1.0,greater than about 0.2 and up to about 1.0, greater than about 0.3 andup to about 1.0, greater than about 0.4 and up to about 1.0, or greaterthan about 0.4 and up to about 1.0. In still other embodiments, thepolymer fraction has a block index greater than about 0.1 and up toabout 0.5, greater than about 0.2 and up to about 0.5, greater thanabout 0.3 and up to about 0.5, or greater than about 0.4 and up to about0.5. In yet other embodiments, the polymer fraction has a block indexgreater than about 0.2 and up to about 0.9, greater than about 0.3 andup to about 0.8, greater than about 0.4 and up to about 0.7, or greaterthan about 0.5 and up to about 0.6.

For copolymers of ethylene and an α-olefin, the inventive polymerspreferably possess (1) a PDI of at least 1.3, more preferably at least1.5, at least 1.7, or at least 2.0, and most preferably at least 2.6, upto a maximum value of 5.0, more preferably up to a maximum of 3.5, andespecially up to a maximum of 2.7; (2) a heat of fusion of 80 J/g orless; (3) an ethylene content of at least 50 weight percent; (4) a glasstransition temperature, T_(g), of less than −25° C., more preferablyless than −30° C., and/or (5) one and only one T_(m).

Further, the inventive polymers can have, alone or in combination withany other properties disclosed herein, a storage modulus, G′, such thatlog(G′) is greater than or equal to 400 kPa, preferably greater than orequal to 1.0 MPa, at a temperature of 100° C. Moreover, the inventivepolymers possess a relatively flat storage modulus as a function oftemperature in the range from 0 to 100° C. (illustrated in FIG. 6) thatis characteristic of block copolymers, and heretofore unknown for anolefin copolymer, especially a copolymer of ethylene and one or moreC₃₋₈ aliphatic α-olefins. (By the term “relatively flat” in this contextis meant that log G′ (in Pascals) decreases by less than one order ofmagnitude between 50 and 100° C., preferably between 0 and 100° C.).

The inventive interpolymers may be further characterized by athermomechanical analysis penetration depth of 1 mm at a temperature ofat least 90° C. as well as a flexural modulus of from 3 kpsi (20 MPa) to13 kpsi (90 MPa). Alternatively, the inventive interpolymers can have athermomechanical analysis penetration depth of 1 mm at a temperature ofat least 104° C. as well as a flexural modulus of at least 3 kpsi (20MPa). They may be characterized as having an abrasion resistance (orvolume loss) of less than 90 mm³. FIG. 7 shows the TMA (1 mm) versusflex modulus for the inventive polymers, as compared to other knownpolymers. The inventive polymers have significantly betterflexibility-heat resistance balance than the other polymers.

Additionally, the ethylene/α-olefin interpolymers can have a melt index,12, from 0.01 to 2000 g/10 minutes, preferably from 0.01 to 1000 g/10minutes, more preferably from 0.01 to 500 g/10 minutes, and especiallyfrom 0.01 to 100 g/10 minutes. In certain embodiments, theethylene/α-olefin interpolymers have a melt index, 12, from 0.01 to 10g/10 minutes, from 0.5 to 50 g/10 minutes, from 1 to 30 g/10 minutes,from 1 to 6 g/10 minutes or from 0.3 to 10 g/10 minutes. In certainembodiments, the melt index for the ethylene/α-olefin polymers is 1 g/10minutes, 3 g/10 minutes or 5 g/10 minutes.

The polymers can have molecular weights, M_(w), from 1,000 g/mole to5,000,000 g/mole, preferably from 1000 g/mole to 1,000,000, morepreferably from 10,000 g/mole to 500,000 g/mole, and especially from10,000 g/mole to 300,000 g/mole. The density of the inventive polymerscan be from 0.80 to 0.99 g/cm³ and preferably for ethylene containingpolymers from 0.85 g/cm³ to 0.97 g/cm³. In certain embodiments, thedensity of the ethylene/α-olefin polymers ranges from 0.860 to 0.925g/cm³ or 0.867 to 0.910 g/cm³.

The process of making the polymers has been disclosed in the followingpatent applications: U.S. Provisional Application No. 60/553,906, filedMar. 17, 2004; U.S. Provisional Application No. 60/662,937, filed Mar.17, 2005; U.S. Provisional Application No. 60/662,939, filed Mar. 17,2005; U.S. Provisional Application No. 60/566,2938, filed Mar. 17, 2005;PCT Application No. PCT/US2005/008916, filed Mar. 17, 2005; PCTApplication No. PCT/US2005/008915, filed Mar. 17, 2005; and PCTApplication No. PCT/US2005/008917, filed Mar. 17, 2005, all of which areincorporated by reference herein in their entirety. For example, onesuch method comprises contacting ethylene and optionally one or moreaddition polymerizable monomers other than ethylene under additionpolymerization conditions with a catalyst composition comprising:

-   -   the admixture or reaction product resulting from combining:    -   (A) a first olefin polymerization catalyst having a high        comonomer incorporation index,    -   (B) a second olefin polymerization catalyst having a comonomer        incorporation index less than 90 percent, preferably less than        50 percent, most preferably less than 5 percent of the comonomer        incorporation index of catalyst (A), and    -   (C) a chain shuttling agent.

Representative catalysts and chain shuttling agent are as follows.

Catalyst (A1) is[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl, prepared according to the teachings of WO 03/40195,2003US0204017, U.S. Ser. No. 10/429,024, filed May 2, 2003, and WO04/24740.

Catalyst (A2) is[N-(2,6-di(1-methylethyl)phenyl)amido)(2-methylphenyl)(1,2-phenylene-(6-pyridin-2-diyl)methane)]hafniumdimethyl, prepared according to the teachings of WO 03/40195,2003US0204017, U.S. Ser. No. 10/429,024, filed May 2, 2003, and WO04/24740.

Catalyst (A3) isbis[N,N′″-(2,4,6-tri(methylphenyl)amido)ethylenediamine]hafniumdibenzyl.

Catalyst (A4) isbis((2-oxoyl-3-(dibenzo-1H-pyrrole-1-yl)-5-(methyl)phenyl)-2-phenoxymethyl)cyclohexane-1,2-diylzirconium (IV) dibenzyl, prepared substantially according to theteachings of US-A-2004/0010103.

Catalyst (B1) is1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconium dibenzyl

Catalyst (B2) is1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(2-methylcyclohexyl)-immino)methyl)(2-oxoyl)zirconium dibenzyl

Catalyst (C1) is(t-butylamido)dimethyl(3-N-pyrrolyl-1,2,3,3a,7a-η-inden-1-yl)silanetitaniumdimethyl prepared substantially according to the techniques of U.S. Pat.No. 6,268,444:

Catalyst (C2) is(t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,7a-η-inden-1-yl)silanetitaniumdimethyl prepared substantially according to the teachings ofUS-A-2003/004286:

Catalyst (C3) is(t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,8a-η-s-indacen-1-yl)silanetitaniumdimethyl prepared substantially according to the teachings ofUS-A-2003/004286:

Catalyst (D1) is bis(dimethyldisiloxane)(indene-1-yl)zirconiumdichloride available from Sigma-Aldrich:

Shuttling Agents The shuttling agents employed include diethylzinc,di(1-butyl)zinc, di(n-hexyl)zinc, triethylaluminum, trioctylaluminum,triethylgallium, i-butylaluminum bis(dimethyl(t-butyl)siloxane),i-butylaluminum bis(di(trimethylsilyl)amide), n-octylaluminumdi(pyridine-2-methoxide), bis(n-octadecyl)i-butylaluminum,i-butylaluminum bis(di(n-pentyl)amide), n-octylaluminumbis(2,6-di-t-butylphenoxide, n-octylaluminum di(ethyl(1-naphthyl)amide),ethylaluminum bis(t-butyldimethylsiloxide), ethylaluminumdi(bis(trimethylsilyl)amide), ethylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminumbis(dimethyl(t-butyl)siloxide, ethylzinc (2,6-diphenylphenoxide), andethylzinc (t-butoxide).

Preferably, the foregoing process takes the form of a continuoussolution process for forming block copolymers, especially multi-blockcopolymers, preferably linear multi-block copolymers of two or moremonomers, more especially ethylene and a C₃₋₂₀ olefin or cycloolefin,and most especially ethylene and a C₄₋₂₀ α-olefin, using multiplecatalysts that are incapable of interconversion. That is, the catalystsare chemically distinct. Under continuous solution polymerizationconditions, the process is ideally suited for polymerization of mixturesof monomers at high monomer conversions. Under these polymerizationconditions, shuttling from the chain shuttling agent to the catalystbecomes advantaged compared to chain growth, and multi-block copolymers,especially linear multi-block copolymers are formed in high efficiency.

The inventive interpolymers may be differentiated from conventional,random copolymers, physical blends of polymers, and block copolymersprepared via sequential monomer addition, fluxional catalysts, anionicor cationic living polymerization techniques. In particular, compared toa random copolymer of the same monomers and monomer content atequivalent crystallinity or modulus, the inventive interpolymers havebetter (higher) heat resistance as measured by melting point, higher TMApenetration temperature, higher high-temperature tensile strength,and/or higher high-temperature torsion storage modulus as determined bydynamic mechanical analysis. Compared to a random copolymer containingthe same monomers and monomer content, the inventive interpolymers havelower compression set, particularly at elevated temperatures such asbody temperature or higher, lower stress relaxation, lower stressrelaxation particularly at body temperature or higher, higher creepresistance, higher tear strength, higher blocking resistance, fastersetup due to higher crystallization (solidification) temperature, higherrecovery (particularly at elevated temperatures), better abrasionresistance, higher retractive force, and better oil and filleracceptance.

The inventive interpolymers also exhibit a unique crystallization andbranching distribution relationship. That is, the inventiveinterpolymers have a relatively large difference between the tallestpeak temperature measured using CRYSTAF and DSC as a function of heat offusion, especially as compared to random copolymers containing the samemonomers and monomer level or physical blends of polymers, such as ablend of a high density polymer and a lower density copolymer, atequivalent overall density. It is believed that this unique feature ofthe inventive interpolymers is due to the unique distribution of thecomonomer in blocks within the polymer backbone. In particular, theinventive interpolymers may comprise alternating blocks of differingcomonomer content (including homopolymer blocks). The inventiveinterpolymers may also comprise a distribution in number and/or blocksize of polymer blocks of differing density or comonomer content, whichis a Schultz-Flory type of distribution. In addition, the inventiveinterpolymers also have a unique peak melting point and crystallizationtemperature profile that is substantially independent of polymerdensity, modulus, and morphology. In a preferred embodiment, themicrocrystalline order of the polymers demonstrates characteristicspherulites and lamellae that are distinguishable from random or blockcopolymers, even at PDI values that are less than 1.7, or even less than1.5, down to less than 1.3.

Moreover, the inventive interpolymers may be prepared using techniquesto influence the degree or level of blockiness. That is the amount ofcomonomer and length of each polymer block or segment can be altered bycontrolling the ratio and type of catalysts and shuttling agent as wellas the temperature of the polymerization, and other polymerizationvariables. A surprising benefit of this phenomenon is the discovery thatas the degree of blockiness is increased, the optical properties, tearstrength, and high temperature recovery properties of the resultingpolymer are improved. In particular, haze decreases while clarity, tearstrength, and high temperature recovery properties increase as theaverage number of blocks in the polymer increases. By selectingshuttling agents and catalyst combinations having the desired chaintransferring ability (high rates of shuttling with low levels of chaintermination) other forms of polymer termination are effectivelysuppressed. Accordingly, little if any β-hydride elimination is observedin the polymerization of ethylene/α-olefin comonomer mixtures accordingto embodiments of the invention, and the resulting crystalline blocksare highly, or substantially completely, linear, possessing little or nolong chain branching.

Polymers with highly crystalline chain ends can be selectively preparedin accordance with embodiments of the invention. In elastomerapplications, reducing the relative quantity of polymer that terminateswith an amorphous block reduces the intermolecular dilutive effect oncrystalline regions. This result can be obtained by choosing chainshuttling agents and catalysts having an appropriate response tohydrogen or other chain terminating agents. Specifically, if thecatalyst which produces highly crystalline polymer is more susceptibleto chain termination (such as by use of hydrogen) than the catalystresponsible for producing the less crystalline polymer segment (such asthrough higher comonomer incorporation, regio-error, or atactic polymerformation), then the highly crystalline polymer segments willpreferentially populate the terminal portions of the polymer. Not onlyare the resulting terminated groups crystalline, but upon termination,the highly crystalline polymer forming catalyst site is once againavailable for reinitiation of polymer formation. The initially formedpolymer is therefore another highly crystalline polymer segment.Accordingly, both ends of the resulting multi-block copolymer arepreferentially highly crystalline.

The ethylene α-olefin interpolymers used in the embodiments of theinvention are preferably interpolymers of ethylene with at least oneC₃-C₂₀ α-olefin. Copolymers of ethylene and a C₃-C₂₀ α-olefin areespecially preferred. The interpolymers may further comprise C₄-C₁₁diolefin and/or alkenylbenzene. Suitable unsaturated comonomers usefulfor polymerizing with ethylene include, for example, ethylenicallyunsaturated monomers, conjugated or nonconjugated dienes, polyenes,alkenylbenzenes, etc. Examples of such comonomers include C₃-C₂₀α-olefins such as propylene, isobutylene, 1-butene, 1-hexene, 1-pentene,4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and thelike. 1 Butene and 1-octene are especially preferred. Other suitablemonomers include styrene, halo- or alkyl-substituted styrenes,vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and naphthenics(e.g., cyclopentene, cyclohexene and cyclooctene).

While ethylene/α-olefin interpolymers are preferred polymers, otherethylene/olefin polymers may also be used. Olefins as used herein referto a family of unsaturated hydrocarbon-based compounds with at least onecarbon-carbon double bond. Depending on the selection of catalysts, anyolefin may be used in embodiments of the invention. Preferably, suitableolefins are C₃-C₂₀ aliphatic and aromatic compounds containing vinylicunsaturation, as well as cyclic compounds, such as cyclobutene,cyclopentene, dicyclopentadiene, and norbornene, including but notlimited to, norbornene substituted in the 5 and 6 position with C₁-C₂₀hydrocarbyl or cyclohydrocarbyl groups. Also included are mixtures ofsuch olefins as well as mixtures of such olefins with C₄-C₄₀ diolefincompounds.

Examples of olefin monomers include, but are not limited to propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decene, and 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene,4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene,vinylcyclohexane, norbornadiene, ethylidene norbornene, cyclopentene,cyclohexene, dicyclopentadiene, cyclooctene, C₄-C₄₀ dienes, includingbut not limited to 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene,1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, other C₄-C₄₀ α-olefins, andthe like. In certain embodiments, the α-olefin is propylene, 1-butene,1-pentene, 1-hexene, 1-octene or a combination thereof. Although anyhydrocarbon containing a vinyl group potentially may be used inembodiments of the invention, practical issues such as monomeravailability, cost, and the ability to conveniently remove unreactedmonomer from the resulting polymer may become more problematic as themolecular weight of the monomer becomes too high.

The polymerization processes described herein are well suited for theproduction of olefin polymers comprising monovinylidene aromaticmonomers including styrene, o-methyl styrene, p-methyl styrene,t-butylstyrene, and the like. In particular, interpolymers comprisingethylene and styrene can be prepared by following the teachings herein.Optionally, copolymers comprising ethylene, styrene and a C₃-C₂₀ alphaolefin, optionally comprising a C₄-C₂₀ diene, having improved propertiescan be prepared.

Suitable non-conjugated diene monomers can be a straight chain, branchedchain or cyclic hydrocarbon diene having from 6 to 15 carbon atoms.Examples of suitable non-conjugated dienes include, but are not limitedto, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6-octadiene,1,7-octadiene, 1,9-decadiene, branched chain acyclic dienes, such as5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;3,7-dimethyl-1,7-octadiene and mixed isomers of dihydromyricene anddihydroocinene, single ring alicyclic dienes, such as1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and1,5-cyclododecadiene, and multi-ring alicyclic fused and bridged ringdienes, such as tetrahydroindene, methyl tetrahydroindene,dicyclopentadiene, bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene,cycloalkenyl and cycloalkylidene norbornenes, such as5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene,5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, and norbornadiene.Of the dienes typically used to prepare EPDMs, the particularlypreferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene(ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB),and dicyclopentadiene (DCPD). The especially preferred dienes are5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).

One class of desirable polymers that can be made in accordance withembodiments of the invention are elastomeric interpolymers of ethylene,a C₃-C₂₀ α-olefin, especially propylene, and optionally one or morediene monomers. Preferred α-olefins for use in this embodiment of thepresent invention are designated by the formula CH₂═CHR*, where R* is alinear or branched alkyl group of from 1 to 12 carbon atoms. Examples ofsuitable α-olefins include, but are not limited to, propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and1-octene. A particularly preferred α-olefin is propylene. The propylenebased polymers are generally referred to in the art as EP or EPDMpolymers. Suitable dienes for use in preparing such polymers, especiallymulti-block EPDM type polymers include conjugated or non-conjugated,straight or branched chain-, cyclic- or polycyclic-dienes comprisingfrom 4 to 20 carbons. Preferred dienes include 1,4-pentadiene,1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene,cyclohexadiene, and 5-butylidene-2-norbornene. A particularly preferreddiene is 5-ethylidene-2-norbornene.

Because the diene containing polymers comprise alternating segments orblocks containing greater or lesser quantities of the diene (includingnone) and α-olefin (including none), the total quantity of diene andα-olefin may be reduced without loss of subsequent polymer properties.That is, because the diene and α-olefin monomers are preferentiallyincorporated into one type of block of the polymer rather than uniformlyor randomly throughout the polymer, they are more efficiently utilizedand subsequently the crosslink density of the polymer can be bettercontrolled. Such crosslinkable elastomers and the cured products haveadvantaged properties, including higher tensile strength and betterelastic recovery.

In some embodiments, the inventive interpolymers made with two catalystsincorporating differing quantities of comonomer have a weight ratio ofblocks formed thereby from 95:5 to 5:95. The elastomeric polymersdesirably have an ethylene content of from 20 to 90 percent, a dienecontent of from 0.1 to 10 percent, and an α-olefin content of from 10 to80 percent, based on the total weight of the polymer. Furtherpreferably, the multi-block elastomeric polymers have an ethylenecontent of from 60 to 90 percent, a diene content of from 0.1 to 10percent, and an α-olefin content of from 10 to 40 percent, based on thetotal weight of the polymer. Preferred polymers are high molecularweight polymers, having a weight average molecular weight (Mw) from10,000 to about 2,500,000, preferably from 20,000 to 500,000, morepreferably from 20,000 to 350,000, and a polydispersity less than 3.5,more preferably less than 3.0, and a Mooney viscosity (ML (1+4) 125° C.)from 1 to 250. More preferably, such polymers have an ethylene contentfrom 65 to 75 percent, a diene content from 0 to 6 percent, and anα-olefin content from 20 to 35 percent.

The ethylene/α-olefin interpolymers can be functionalized byincorporating at least one functional group in its polymer structure.Exemplary functional groups may include, for example, ethylenicallyunsaturated mono- and di-functional carboxylic acids, ethylenicallyunsaturated mono- and di-functional carboxylic acid anhydrides, saltsthereof and esters thereof. Such functional groups may be grafted to anethylene/α-olefin interpolymer, or it may be copolymerized with ethyleneand an optional additional comonomer to form an interpolymer ofethylene, the functional comonomer and optionally other comonomer(s).Means for grafting functional groups onto polyethylene are described forexample in U.S. Pat. Nos. 4,762,890, 4,927,888, and 4,950,541, thedisclosures of these patents are incorporated herein by reference intheir entirety. One particularly useful functional group is malicanhydride.

The amount of the functional group present in the functionalinterpolymer can vary. The functional group can typically be present ina copolymer-type functionalized interpolymer in an amount of at leastabout 1.0 weight percent, preferably at least about 5 weight percent,and more preferably at least about 7 weight percent. The functionalgroup will typically be present in a copolymer-type functionalizedinterpolymer in an amount less than about 40 weight percent, preferablyless than about 30 weight percent, and more preferably less than about25 weight percent.

Testing Methods

In the examples that follow, the following analytical techniques areemployed:

GPC Method for Samples 1-4 and A-C

An automated liquid-handling robot equipped with a heated needle set to160° C. is used to add enough 1,2,4-trichlorobenzene stabilized with 300ppm Ionol to each dried polymer sample to give a final concentration of30 μg/mL. A small glass stir rod is placed into each tube and thesamples are heated to 160° C. for 2 hours on a heated, orbital-shakerrotating at 250 rpm. The concentrated polymer solution is then dilutedto 1 mg/ml using the automated liquid-handling robot and the heatedneedle set to 160° C.

A Symyx Rapid GPC system is used to determine the molecular weight datafor each sample. A Gilson 350 pump set at 2.0 ml/min flow rate is usedto pump helium-purged 1,2-dichlorobenzene stabilized with 300 ppm Ionolas the mobile phase through three Plgel 10 micrometer (μm) Mixed B 300mm×7.5 mm columns placed in series and heated to 160° C. A Polymer LabsELS1000 Detector is used with the Evaporator set to 250° C., theNebulizer set to 165° C., and the nitrogen flow rate set to 1.8 SLM at apressure of 60-80 psi (400−600 kPa) N₂. The polymer samples are heatedto 160° C. and each sample injected into a 250 μl loop using theliquid-handling robot and a heated needle. Serial analysis of thepolymer samples using two switched loops and overlapping injections areused. The sample data is collected and analyzed using Symyx Epoch™software. Peaks are manually integrated and the molecular weightinformation reported uncorrected against a polystyrene standardcalibration curve.

Standard CRYSTAF Method

Branching distributions are determined by crystallization analysisfractionation (CRYSTAF) using a CRYSTAF 200 unit commercially availablefrom PolymerChar, Valencia, Spain. The samples are dissolved in 1,2,4trichlorobenzene at 160° C. (0.66 mg/mL) for 1 hr and stabilized at 95°C. for 45 minutes. The sampling temperatures range from 95 to 30° C. ata cooling rate of 0.2° C./min. An infrared detector is used to measurethe polymer solution concentrations. The cumulative solubleconcentration is measured as the polymer crystallizes while thetemperature is decreased. The analytical derivative of the cumulativeprofile reflects the short chain branching distribution of the polymer.

The CRYSTAF peak temperature and area are identified by the peakanalysis module included in the CRYSTAF Software (Version 2001.b,PolymerChar, Valencia, Spain). The CRYSTAF peak finding routineidentifies a peak temperature as a maximum in the dW/dT curve and thearea between the largest positive inflections on either side of theidentified peak in the derivative curve. To calculate the CRYSTAF curve,the preferred processing parameters are with a temperature limit of 70°C. and with smoothing parameters above the temperature limit of 0.1, andbelow the temperature limit of 0.3.

DSC Standard Method (Excluding Samples 1-4 and A-C)

Differential Scanning Calorimetry results are determined using a TAImodel Q1000 DSC equipped with an RCS cooling accessory and anautosampler. A nitrogen purge gas flow of 50 ml/min is used. The sampleis pressed into a thin film and melted in the press at about 175° C. andthen air-cooled to room temperature (25° C.). 3-10 mg of material isthen cut into a 6 mm diameter disk, accurately weighed, placed in alight aluminum pan (ca 50 mg), and then crimped shut. The thermalbehavior of the sample is investigated with the following temperatureprofile. The sample is rapidly heated to 180° C. and held isothermal for3 minutes in order to remove any previous thermal history. The sample isthen cooled to −40° C. at 10° C./min cooling rate and held at −40° C.for 3 minutes. The sample is then heated to 150° C. at 10° C./min.heating rate. The cooling and second heating curves are recorded.

The DSC melting peak is measured as the maximum in heat flow rate (W/g)with respect to the linear baseline drawn between −30° C. and end ofmelting. The heat of fusion is measured as the area under the meltingcurve between −30° C. and the end of melting using a linear baseline.

GPC Method (Excluding Samples 1-4 and A-C)

The gel permeation chromatographic system consists of either a PolymerLaboratories Model PL-210 or a Polymer Laboratories Model PL-220instrument. The column and carousel compartments are operated at 140° C.Three Polymer Laboratories 10-micron Mixed-B columns are used. Thesolvent is 1,2,4 trichlorobenzene. The samples are prepared at aconcentration of 0.1 grams of polymer in 50 milliliters of solventcontaining 200 ppm of butylated hydroxytoluene (BHT). Samples areprepared by agitating lightly for 2 hours at 160° C. The injectionvolume used is 100 microliters and the flow rate is 1.0 ml/minute.

Calibration of the GPC column set is performed with 21 narrow molecularweight distribution polystyrene standards with molecular weights rangingfrom 580 to 8,400,000, arranged in 6 “cocktail” mixtures with at least adecade of separation between individual molecular weights. The standardsare purchased from Polymer Laboratories (Shropshire, UK). Thepolystyrene standards are prepared at 0.025 grams in 50 milliliters ofsolvent for molecular weights equal to or greater than 1,000,000, and0.05 grams in 50 milliliters of solvent for molecular weights less than1,000,000. The polystyrene standards are dissolved at 80° C. with gentleagitation for 30 minutes. The narrow standards mixtures are run firstand in order of decreasing highest molecular weight component tominimize degradation. The polystyrene standard peak molecular weightsare converted to polyethylene molecular weights using the followingequation (as described in Williams and Ward, J. Polym. Sci., Polym.Let., 6, 621 (1968)): M_(polyethylene)=0.431(M_(polystyrene)).

Polyethylene equivalent molecular weight calculations are performedusing Viscotek TriSEC software Version 3.0.

Compression Set

Compression set is measured according to ASTM D 395. The sample isprepared by stacking 25.4 mm diameter round discs of 3.2 mm, 2.0 mm, and0.25 mm thickness until a total thickness of 12.7 mm is reached. Thediscs are cut from 12.7 cm×12.7 cm compression molded plaques moldedwith a hot press under the following conditions: zero pressure for 3 minat 190° C., followed by 86 MPa for 2 min at 190° C., followed by coolinginside the press with cold running water at 86 MPa.

Density

Samples for density measurement are prepared according to ASTM D 1928.Measurements are made within one hour of sample pressing using ASTMD792, Method B.

Flexural/Secant Modulus/Storage Modulus

Samples are compression molded using ASTM D 1928. Flexural and 2 percentsecant moduli are measured according to ASTM D-790. Storage modulus ismeasured according to ASTM D 5026-01 or equivalent technique.

Optical Properties

Films of 0.4 mm thickness are compression molded using a hot press(Carver Model #4095-4PR1001R). The pellets are placed betweenpolytetrafluoroethylene sheets, heated at 190° C. at 55 psi (380 kPa)for 3 min, followed by 1.3 MPa for 3 min, and then 2.6 MPa for 3 min.The film is then cooled in the press with running cold water at 1.3 MPafor 1 min. The compression molded films are used for opticalmeasurements, tensile behavior, recovery, and stress relaxation.

Clarity is measured using BYK Gardner Haze-gard as specified in ASTM D1746.

45° gloss is measured using BYK Gardner Glossmeter Microgloss 45° asspecified in ASTM D-2457.

Internal haze is measured using BYK Gardner Haze-gard based on ASTM D1003 Procedure A. Mineral oil is applied to the film surface to removesurface scratches.

Mechanical Properties—Tensile, Hysteresis, and Tear

Stress-strain behavior in uniaxial tension is measured using ASTM D 1708microtensile specimens. Samples are stretched with an Instron at 500%min⁻¹ at 21° C. Tensile strength and elongation at break are reportedfrom an average of 5 specimens.

100% and 300% Hysteresis is determined from cyclic loading to 100% and300% strains using ASTM D 1708 microtensile specimens with an Instron™instrument. The sample is loaded and unloaded at 267% min⁻¹ for 3 cyclesat 21° C. Cyclic experiments at 300% and 80° C. are conducted using anenvironmental chamber. In the 80° C. experiment, the sample is allowedto equilibrate for 45 minutes at the test temperature before testing. Inthe 21° C., 300% strain cyclic experiment, the retractive stress at 150%strain from the first unloading cycle is recorded. Percent recovery forall experiments are calculated from the first unloading cycle using thestrain at which the load returned to the base line. The percent recoveryis defined as:

${\% \mspace{14mu} {Recovery}} = {\frac{ɛ_{f} - ɛ_{s}}{ɛ_{f}} \times 100}$

where ε_(f) is the strain taken for cyclic loading and ε_(s) is thestrain where the load returns to the baseline during the 1^(st)unloading cycle.

Stress relaxation is measured at 50 percent strain and 37° C. for 12hours using an Instron™ instrument equipped with an environmentalchamber. The gauge geometry was 76 mm×25 mm×0.4 mm. After equilibratingat 37° C. for 45 min in the environmental chamber, the sample wasstretched to 50% strain at 333% min⁻¹. Stress was recorded as a functionof time for 12 hours. The percent stress relaxation after 12 hours wascalculated using the formula:

${\% \mspace{14mu} {Stress}\mspace{14mu} {Relaxation}} = {\frac{L_{0} - L_{12}}{L_{0}} \times 100}$

where L₀ is the load at 50% strain at 0 time and L₁₂ is the load at 50percent strain after 12 hours.

Tensile notched tear experiments are carried out on samples having adensity of 0.88 g/cc or less using an Instron™ instrument. The geometryconsists of a gauge section of 76 mm×13 mm×0.4 mm with a 2 mm notch cutinto the sample at half the specimen length. The sample is stretched at508 mm min-1 at 21° C. until it breaks. The tear energy is calculated asthe area under the stress-elongation curve up to strain at maximum load.An average of at least 3 specimens are reported.

TMA

Thermal Mechanical Analysis (Penetration Temperature) is conducted on 30mm diameter×3.3 mm thick, compression molded discs, formed at 180° C.and 10 MPa molding pressure for 5 minutes and then air quenched. Theinstrument used is a TMA 7, brand available from Perkin-Elmer. In thetest, a probe with 1.5 mm radius tip (P/N N519-0416) is applied to thesurface of the sample disc with 1N force. The temperature is raised at5° C./min from 25° C. The probe penetration distance is measured as afunction of temperature. The experiment ends when the probe haspenetrated 1 mm into the sample.

DMA

Dynamic Mechanical Analysis (DMA) is measured on compression moldeddisks formed in a hot press at 180° C. at 10 MPa pressure for 5 minutesand then water cooled in the press at 90° C./min. Testing is conductedusing an ARES controlled strain rheometer (TA instruments) equipped withdual cantilever fixtures for torsion testing.

A 1.5 mm plaque is pressed and cut in a bar of dimensions 32×12 mm. Thesample is clamped at both ends between fixtures separated by 10 mm (gripseparation ΔL) and subjected to successive temperature steps from −100°C. to 200° C. (5° C. per step). At each temperature the torsion modulusG′ is measured at an angular frequency of 10 rad/s, the strain amplitudebeing maintained between 0.1 percent and 4 percent to ensure that thetorque is sufficient and that the measurement remains in the linearregime.

An initial static force of 10 g is maintained (auto-tension mode) toprevent slack in the sample when thermal expansion occurs. As aconsequence, the grip separation ΔL increases with the temperature,particularly above the melting or softening point of the polymer sample.The test stops at the maximum temperature or when the gap between thefixtures reaches 65 mm.

Melt Index

Melt index, or I₂, is measured in accordance with ASTM D 1238, Condition190° C./2.16 kg. Melt index, or I₁₀ is also measured in accordance withASTM D 1238, Condition 190° C./10 kg.

ATREF

Analytical temperature rising elution fractionation (ATREF) analysis isconducted according to the method described in U.S. Pat. No. 4,798,081and Wilde, L.; Ryle, T. R.; Knobeloch, D. C.; Peat, I. R.; Determinationof Branching Distributions in Polyethylene and Ethylene Copolymers, J.Polym. Sci., 20, 441-455 (1982), which are incorporated by referenceherein in their entirety. The composition to be analyzed is dissolved intrichlorobenzene and allowed to crystallize in a column containing aninert support (stainless steel shot) by slowly reducing the temperatureto 20° C. at a cooling rate of 0.1° C./min. The column is equipped withan infrared detector. An ATREF chromatogram curve is then generated byeluting the crystallized polymer sample from the column by slowlyincreasing the temperature of the eluting solvent (trichlorobenzene)from 20 to 120° C. at a rate of 1.5° C./min.

¹³C NMR Analysis

The samples are prepared by adding approximately 3 g of a 50/50 mixtureof tetrachloroethane-d²/orthodichlorobenzene to 0.4 g sample in a 10 mmNMR tube. The samples are dissolved and homogenized by heating the tubeand its contents to 150° C. The data are collected using a JEOL Eclipse™400 MHz spectrometer or a Varian Unity Plus™ 400 MHz spectrometer,corresponding to a ¹³C resonance frequency of 100.5 MHz. The data areacquired using 4000 transients per data file with a 6 second pulserepetition delay. To achieve minimum signal-to-noise for quantitativeanalysis, multiple data files are added together. The spectral width is25,000 Hz with a minimum file size of 32K data points. The samples areanalyzed at 130° C. in a 10 mm broad band probe. The comonomerincorporation is determined using Randall's triad method (Randall, J.C.; JMS-Rev. Macromol. Chem. Phys., C29, 201-317 (1989), which isincorporated by reference herein in its entirety.

Polymer Fractionation by TREF

Large-scale TREF fractionation is carried by dissolving 15-20 g ofpolymer in 2 liters of 1,2,4-trichlorobenzene (TCB) by stirring for 4hours at 160° C. The polymer solution is forced by 15 psig (100 kPa)nitrogen onto a 3 inch by 4 foot (7.6 cm×12 cm) steel column packed witha 60:40 (v:v) mix of 30-40 mesh (600-425 μm) spherical, technicalquality glass beads (available from Potters Industries, HC 30 Box 20,Brownwood, Tex., 76801) and stainless steel, 0.028″ (0.7 mm) diametercut wire shot (available from Pellets, Inc. 63 Industrial Drive, NorthTonawanda, N.Y., 14120). The column is immersed in a thermallycontrolled oil jacket, set initially to 160° C. The column is firstcooled ballistically to 125° C., then slow cooled to 20° C. at 0.04° C.per minute and held for one hour. Fresh TCB is introduced at about 65ml/min while the temperature is increased at 0.167° C. per minute.

Approximately 2000 ml portions of eluant from the preparative TREFcolumn are collected in a 16 station, heated fraction collector. Thepolymer is concentrated in each fraction using a rotary evaporator untilabout 50 to 100 ml of the polymer solution remains. The concentratedsolutions are allowed to stand overnight before adding excess methanol,filtering, and rinsing (approx. 300-500 ml of methanol including thefinal rinse). The filtration step is performed on a 3 position vacuumassisted filtering station using 5.0 μm polytetrafluoroethylene coatedfilter paper (available from Osmonics Inc., Cat# Z50WP04750). Thefiltrated fractions are dried overnight in a vacuum oven at 60° C. andweighed on an analytical balance before further testing.

Melt Strength

Melt Strength (MS) is measured by using a capillary rheometer fittedwith a 2.1 mm diameter, 20:1 die with an entrance angle of approximately45 degrees. After equilibrating the samples at 190° C. for 10 minutes,the piston is mm at a speed of 1 inch/minute (2.54 cm/minute). Thestandard test temperature is 190° C. The sample is drawn uniaxially to aset of accelerating nips located 100 mm below the die with anacceleration of 2.4 mm/sec². The required tensile force is recorded as afunction of the take-up speed of the nip rolls. The maximum tensileforce attained during the test is defined as the melt strength. In thecase of polymer melt exhibiting draw resonance, the tensile force beforethe onset of draw resonance was taken as melt strength. The meltstrength is recorded in centiNewtons (“cN”).

Catalysts

The term “overnight”, if used, refers to a time of approximately 16-18hours, the term “room temperature”, refers to a temperature of 20-25°C., and the term “mixed alkanes” refers to a commercially obtainedmixture of C₆₋₉ aliphatic hydrocarbons available under the tradedesignation Isopar E®, from ExxonMobil Chemical Company. In the eventthe name of a compound herein does not conform to the structuralrepresentation thereof, the structural representation shall control. Thesynthesis of all metal complexes and the preparation of all screeningexperiments were carried out in a dry nitrogen atmosphere using dry boxtechniques. All solvents used were HPLC grade and were dried beforetheir use.

MMAO refers to modified methylalumoxane, a triisobutylaluminum modifiedmethylalumoxane available commercially from Akzo-Noble Corporation.

The preparation of catalyst (B1) is conducted as follows.

a) Preparation of(1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)methylimine

3,5-Di-t-butylsalicylaldehyde (3.00 g) is added to 10 mL ofisopropylamine. The solution rapidly turns bright yellow. After stirringat ambient temperature for 3 hours, volatiles are removed under vacuumto yield a bright yellow, crystalline solid (97 percent yield).

b) Preparation of1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconiumdibenzyl

A solution of (1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)imine (605mg, 2.2 mmol) in 5 mL toluene is slowly added to a solution ofZr(CH₂Ph)₄ (500 mg, 1.1 mmol) in 50 mL toluene. The resulting darkyellow solution is stirred for 30 min. Solvent is removed under reducedpressure to yield the desired product as a reddish-brown solid.

The preparation of catalyst (B2) is conducted as follows.

a) Preparation of(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine

2-Methylcyclohexylamine (8.44 mL, 64.0 mmol) is dissolved in methanol(90 mL), and di-t-butylsalicaldehyde (10.00 g, 42.67 mmol) is added. Thereaction mixture is stirred for three hours and then cooled to −25° C.for 12 hrs. The resulting yellow solid precipitate is collected byfiltration and washed with cold methanol (2×15 mL), and then dried underreduced pressure. The yield is 11.17 g of a yellow solid. ¹H NMR isconsistent with the desired product as a mixture of isomers.

b) Preparation ofbis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconiumdibenzyl

A solution of(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine (7.63g, 23.2 mmol) in 200 mL toluene is slowly added to a solution ofZr(CH₂Ph)₄ (5.28 g, 11.6 mmol) in 600 mL toluene. The resulting darkyellow solution is stirred for 1 hour at 25° C. The solution is dilutedfurther with 680 mL toluene to give a solution having a concentration of0.00783 M.

Cocatalyst 1 A mixture of methyldi(C₁₄₋₁₈ alkyl)ammonium salts oftetrakis(pentafluorophenyl)borate (here-in-after armeenium borate),prepared by reaction of a long chain trialkylamine (Armeen™ M2HT,available from Akzo-Nobel, Inc.), HCl and Li[B(C₆F₅)₄], substantially asdisclosed in U.S. Pat. No. 5,919,9883, Ex. 2.

Cocatalyst 2 Mixed C₁₄₋₁₈ alkyldimethylammonium salt ofbis(tris(pentafluorophenyl)-alumane)-2-undecylimidazolide, preparedaccording to U.S. Pat. No. 6,395,671, Ex. 16.

Shuttling Agents The shuttling agents employed include diethylzinc (DEZ,SA1), di(1-butyl)zinc (SA2), di(n-hexyl)zinc (SA3), triethylaluminum(TEA, SA4), trioctylaluminum (SA5), triethylgallium (SA6),i-butylaluminum bis(dimethyl(t-butyl)siloxane) (SA7), i-butylaluminumbis(di(trimethylsilyl)amide) (SA8), n-octylaluminumdi(pyridine-2-methoxide) (SA9), bis(n-octadecyl)i-butylaluminum (SA10),i-butylaluminum bis(di(n-pentyl)amide) (SA11), n-octylaluminumbis(2,6-di-t-butylphenoxide) (SA12), n-octylaluminumdi(ethyl(1-naphthyl)amide) (SA13), ethylaluminumbis(t-butyldimethylsiloxide) (SA14), ethylaluminumdi(bis(trimethylsilyl)amide) (SA15), ethylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA16), n-octylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA17), n-octylaluminumbis(dimethyl(t-butyl)siloxide(SA18), ethylzinc (2,6-diphenylphenoxide)(SA19), and ethylzinc (t-butoxide) (SA20).

EXAMPLES 1-4, COMPARATIVE A-C General High Throughput ParallelPolymerization Conditions

Polymerizations are conducted using a high throughput, parallelpolymerization reactor (PPR) available from Symyx technologies, Inc. andoperated substantially according to U.S. Pat. Nos. 6,248,540, 6,030,917,6,362,309, 6,306,658, and 6,316,663. Ethylene copolymerizations areconducted at 130° C. and 200 psi (1.4 MPa) with ethylene on demand using1.2 equivalents of cocatalyst 1 based on total catalyst used (1.1equivalents when MMAO is present). A series of polymerizations areconducted in a parallel pressure reactor (PPR) contained of 48individual reactor cells in a 6×8 array that are fitted with apre-weighed glass tube. The working volume in each reactor cell is 6000μL. Each cell is temperature and pressure controlled with stirringprovided by individual stirring paddles. The monomer gas and quench gasare plumbed directly into the PPR unit and controlled by automaticvalves. Liquid reagents are robotically added to each reactor cell bysyringes and the reservoir solvent is mixed alkanes. The order ofaddition is mixed alkanes solvent (4 ml), ethylene, 1-octene comonomer(1 ml), cocatalyst 1 or cocatalyst 1/MMAO mixture, shuttling agent, andcatalyst or catalyst mixture. When a mixture of cocatalyst 1 and MMAO ora mixture of two catalysts is used, the reagents are premixed in a smallvial immediately prior to addition to the reactor. When a reagent isomitted in an experiment, the above order of addition is otherwisemaintained. Polymerizations are conducted for approximately 1-2 minutes,until predetermined ethylene consumptions are reached. After quenchingwith CO, the reactors are cooled and the glass tubes are unloaded. Thetubes are transferred to a centrifuge/vacuum drying unit, and dried for12 hours at 60° C. The tubes containing dried polymer are weighed andthe difference between this weight and the tare weight gives the netyield of polymer. Results are contained in Table 1. In Table 1 andelsewhere in the application, comparative compounds are indicated by anasterisk (*).

Examples 1-4 demonstrate the synthesis of linear block copolymers by thepresent invention as evidenced by the formation of a very narrow MWD,essentially monomodal copolymer when DEZ is present and a bimodal, broadmolecular weight distribution product (a mixture of separately producedpolymers) in the absence of DEZ. Due to the fact that Catalyst (A1) isknown to incorporate more octene than Catalyst (B1), the differentblocks or segments of the resulting copolymers of the invention aredistinguishable based on branching or density.

TABLE 1 Cat. (A1) Cat (B1) Cocat MMAO shuttling Ex. (μmol) (μmol) (μmol)(μmol) agent (μmol) Yield (g) Mn Mw/Mn hexyls¹ A* 0.06 — 0.066 0.3 —0.1363 300502 3.32 — B* — 0.1 0.110 0.5 — 0.1581 36957 1.22 2.5 C* 0.060.1 0.176 0.8 — 0.2038 45526 5.30² 5.5 1 0.06 0.1 0.192 — DEZ (8.0)0.1974 28715 1.19 4.8 2 0.06 0.1 0.192 — DEZ (80.0) 0.1468 2161 1.1214.4 3 0.06 0.1 0.192 — TEA (8.0) 0.208 22675 1.71 4.6 4 0.06 0.1 0.192— TEA (80.0) 0.1879 3338 1.54 9.4 ¹C₆ or higher chain content per 1000carbons ²Bimodal molecular weight distribution

It may be seen the polymers produced according to the invention have arelatively narrow polydispersity (Mw/Mn) and larger block-copolymercontent (trimer, tetramer, or larger) than polymers prepared in theabsence of the shuttling agent.

Further characterizing data for the polymers of Table 1 are determinedby reference to the figures. More specifically DSC and ATREF resultsshow the following:

The DSC curve for the polymer of example 1 shows a 115.7° C. meltingpoint (Tm) with a heat of fusion of 158.1 J/g. The corresponding CRYSTAFcurve shows the tallest peak at 34.5° C. with a peak area of 52.9percent. The difference between the DSC Tm and the Tcrystaf is 81.2° C.

The DSC curve for the polymer of example 2 shows a peak with a 109.7° C.melting point (Tm) with a heat of fusion of 214.0 J/g. The correspondingCRYSTAF curve shows the tallest peak at 46.2° C. with a peak area of57.0 percent. The difference between the DSC Tm and the Tcrystaf is63.5° C.

The DSC curve for the polymer of example 3 shows a peak with a 120.7° C.melting point (Tm) with a heat of fusion of 160.1 J/g. The correspondingCRYSTAF curve shows the tallest peak at 66.1° C. with a peak area of71.8 percent. The difference between the DSC Tm and the Tcrystaf is54.6° C.

The DSC curve for the polymer of example 4 shows a peak with a 104.5° C.melting point (Tm) with a heat of fusion of 170.7 J/g. The correspondingCRYSTAF curve shows the tallest peak at 30° C. with a peak area of 18.2percent. The difference between the DSC Tm and the Tcrystaf is 74.5° C.

The DSC curve for comparative A shows a 90.0° C. melting point (Tm) witha heat of fusion of 86.7 J/g. The corresponding CRYSTAF curve shows thetallest peak at 48.5° C. with a peak area of 29.4 percent. Both of thesevalues are consistent with a resin that is low in density. Thedifference between the DSC Tm and the Tcrystaf is 41.8° C.

The DSC curve for comparative B shows a 129.8° C. melting point (Tm)with a heat of fusion of 237.0 J/g. The corresponding CRYSTAF curveshows the tallest peak at 82.4° C. with a peak area of 83.7 percent.Both of these values are consistent with a resin that is high indensity. The difference between the DSC Tm and the Tcrystaf is 47.4° C.

The DSC curve for comparative C shows a 125.3° C. melting point (Tm)with a heat of fusion of 143.0 J/g. The corresponding CRYSTAF curveshows the tallest peak at 81.8° C. with a peak area of 34.7 percent aswell as a lower crystalline peak at 52.4° C. The separation between thetwo peaks is consistent with the presence of a high crystalline and alow crystalline polymer. The difference between the DSC Tm and theTcrystaf is 43.5° C.

EXAMPLES 5-19, COMPARATIVES D-F Continuous Solution Polymerization,Catalyst A1/B2+DEZ

Continuous solution polymerizations are carried out in a computercontrolled autoclave reactor equipped with an internal stirrer. Purifiedmixed alkanes solvent (Isopar™ E available from ExxonMobil ChemicalCompany), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, andhydrogen (where used) are supplied to a 3.8 L reactor equipped with ajacket for temperature control and an internal thermocouple. The solventfeed to the reactor is measured by a mass-flow controller. A variablespeed diaphragm pump controls the solvent flow rate and pressure to thereactor. At the discharge of the pump, a side stream is taken to provideflush flows for the catalyst and cocatalyst 1 injection lines and thereactor agitator. These flows are measured by Micro-Motion mass flowmeters and controlled by control valves or by the manual adjustment ofneedle valves. The remaining solvent is combined with 1-octene,ethylene, and hydrogen (where used) and fed to the reactor. A mass flowcontroller is used to deliver hydrogen to the reactor as needed. Thetemperature of the solvent/monomer solution is controlled by use of aheat exchanger before entering the reactor. This stream enters thebottom of the reactor. The catalyst component solutions are meteredusing pumps and mass flow meters and are combined with the catalystflush solvent and introduced into the bottom of the reactor. The reactoris run liquid-full at 500 psig (3.45 MPa) with vigorous stirring.Product is removed through exit lines at the top of the reactor. Allexit lines from the reactor are steam traced and insulated.Polymerization is stopped by the addition of a small amount of waterinto the exit line along with any stabilizers or other additives andpassing the mixture through a static mixer. The product stream is thenheated by passing through a heat exchanger before devolatilization. Thepolymer product is recovered by extrusion using a devolatilizingextruder and water cooled pelletizer. Process details and results arecontained in Table 2. Selected polymer properties are provided in Table3.

TABLE 2 Process details for preparation of exemplary polymers Cat Cat A1Cat B2 DEZ Cocat Cocat Poly C₈H₁₆ Solv. H₂ T A1² Flow B2³ Flow DEZ FlowConc. Flow [C₂H₄]/ Rate⁵ Ex. kg/hr kg/hr sccm¹ ° C. ppm kg/hr ppm kg/hrConc % kg/hr ppm kg/hr [DEZ]⁴ kg/hr Conv %⁶ Solids % Eff.⁷ D* 1.63 12.729.90 120 142.2 0.14 — — 0.19 0.32 820 0.17 536 1.81 88.8 11.2 95.2 E* ″9.5 5.00 ″ — — 109 0.10 0.19 ″ 1743 0.40 485 1.47 89.9 11.3 126.8 F* ″11.3 251.6 ″ 71.7 0.06 30.8 0.06 — — ″ 0.11 — 1.55 88.5 10.3 257.7  5 ″″ — ″ ″ 0.14 30.8 0.13 0.17 0.43 ″ 0.26 419 1.64 89.6 11.1 118.3  6 ″ ″4.92 ″ ″ 0.10 30.4 0.08 0.17 0.32 ″ 0.18 570 1.65 89.3 11.1 172.7  7 ″ ″21.70 ″ ″ 0.07 30.8 0.06 0.17 0.25 ″ 0.13 718 1.60 89.2 10.6 244.1  8 ″″ 36.90 ″ ″ 0.06 ″ ″ ″ 0.10 ″ 0.12 1778 1.62 90.0 10.8 261.1  9 ″ ″78.43 ″ ″ ″ ″ ″ ″ 0.04 ″ ″ 4596 1.63 90.2 10.8 267.9 10 ″ ″ 0.00 12371.1 0.12 30.3 0.14 0.34 0.19 1743 0.08 415 1.67 90.31 11.1 131.1 11 ″ ″″ 120 71.1 0.16 ″ 0.17 0.80 0.15 1743 0.10 249 1.68 89.56 11.1 100.6 12″ ″ ″ 121 71.1 0.15 ″ 0.07 ″ 0.09 1743 0.07 396 1.70 90.02 11.3 137.0 13″ ″ ″ 122 71.1 0.12 ″ 0.06 ″ 0.05 1743 0.05 653 1.69 89.64 11.2 161.9 14″ ″ ″ 120 71.1 0.05 ″ 0.29 ″ 0.10 1743 0.10 395 1.41 89.42 9.3 114.1 152.45 ″ ″ ″ 71.1 0.14 ″ 0.17 ″ 0.14 1743 0.09 282 1.80 89.33 11.3 121.316 ″ ″ ″ 122 71.1 0.10 ″ 0.13 ″ 0.07 1743 0.07 485 1.78 90.11 11.2 159.717 ″ ″ ″ 121 71.1 0.10 ″ 0.14 ″ 0.08 1743 ″ 506 1.75 89.08 11.0 155.6 180.69 ″ ″ 121 71.1 ″ ″ 0.22 ″ 0.11 1743 0.10 331 1.25 89.93 8.8 90.2 190.32 ″ ″ 122 71.1 0.06 ″ ″ ″ 0.09 1743 0.08 367 1.16 90.74 8.4 106.0*Comparative, not an example of the invention ¹standard cm³/min²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconium dibenzyl ⁴molar ratio in reactor ⁵polymer production rate⁶percent ethylene conversion in reactor ⁷efficiency, kg polymer/g Mwhere g M = g Hf + g Zr

TABLE 3 Properties of exemplary polymers Heat of CRYSTAF Density Mw MnFusion T_(m) T_(c) T_(CRYSTAF) Tm − T_(CRYSTAF) Peak Area Ex. (g/cm³) I₂I₁₀ I₁₀/I₂ (g/mol) (g/mol) Mw/Mn (J/g) (° C.) (° C.) (° C.) (° C.)(percent) D* 0.8627 1.5 10.0 6.5 110,000 55,800 2.0 32 37 45 30 7 99 E*0.9378 7.0 39.0 5.6 65,000 33,300 2.0 183 124 113 79 45 95 F* 0.8895 0.912.5 13.4 137,300 9,980 13.8 90 125 111 78 47 20  5 0.8786 1.5 9.8 6.7104,600 53,200 2.0 55 120 101 48 72 60  6 0.8785 1.1 7.5 6.5 10960053300 2.1 55 115 94 44 71 63  7 0.8825 1.0 7.2 7.1 118,500 53,100 2.2 69121 103 49 72 29  8 0.8828 0.9 6.8 7.7 129,000 40,100 3.2 68 124 106 8043 13  9 0.8836 1.1 9.7 9.1 129600 28700 4.5 74 125 109 81 44 16 100.8784 1.2 7.5 6.5 113,100 58,200 1.9 54 116 92 41 75 52 11 0.8818 9.159.2 6.5 66,200 36,500 1.8 63 114 93 40 74 25 12 0.8700 2.1 13.2 6.4101,500 55,100 1.8 40 113 80 30 83 91 13 0.8718 0.7 4.4 6.5 132,10063,600 2.1 42 114 80 30 81 8 14 0.9116 2.6 15.6 6.0 81,900 43,600 1.9123 121 106 73 48 92 15 0.8719 6.0 41.6 6.9 79,900 40,100 2.0 33 114 9132 82 10 16 0.8758 0.5 3.4 7.1 148,500 74,900 2.0 43 117 96 48 69 65 170.8757 1.7 11.3 6.8 107,500 54,000 2.0 43 116 96 43 73 57 18 0.9192 4.124.9 6.1 72,000 37,900 1.9 136 120 106 70 50 94 19 0.9344 3.4 20.3 6.076,800 39,400 1.9 169 125 112 80 45 88

The resulting polymers are tested by DSC and ATREF as with previousexamples. Results are as follows:

The DSC curve for the polymer of example 5 shows a peak with a 119.6° C.melting point (Tm) with a heat of fusion of 60.0 J/g. The correspondingCRYSTAF curve shows the tallest peak at 47.6° C. with a peak area of59.5 percent. The delta between the DSC Tm and the Tcrystaf is 72.0° C.

The DSC curve for the polymer of example 6 shows a peak with a 115.2° C.melting point (Tm) with a heat of fusion of 60.4 J/g. The correspondingCRYSTAF curve shows the tallest peak at 44.2° C. with a peak area of62.7 percent. The delta between the DSC Tm and the Tcrystaf is 71.0° C.

The DSC curve for the polymer of example 7 shows a peak with a 121.3° C.melting point with a heat of fusion of 69.1 μg. The correspondingCRYSTAF curve shows the tallest peak at 49.2° C. with a peak area of29.4 percent. The delta between the DSC Tm and the Tcrystaf is 72.1° C.

The DSC curve for the polymer of example 8 shows a peak with a 123.5° C.melting point (Tm) with a heat of fusion of 67.9 J/g. The correspondingCRYSTAF curve shows the tallest peak at 80.1° C. with a peak area of12.7 percent. The delta between the DSC Tm and the Tcrystaf is 43.4° C.

The DSC curve for the polymer of example 9 shows a peak with a 124.6° C.melting point (Tm) with a heat of fusion of 73.5 μg. The correspondingCRYSTAF curve shows the tallest peak at 80.8° C. with a peak area of16.0 percent. The delta between the DSC Tm and the Tcrystaf is 43.8° C.

The DSC curve for the polymer of example 10 shows a peak with a 115.6°C. melting point (Tm) with a heat of fusion of 60.7 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 40.9° C. with apeak area of 52.4 percent. The delta between the DSC Tm and the Tcrystafis 74.7° C.

The DSC curve for the polymer of example 11 shows a peak with a 113.6°C. melting point (Tm) with a heat of fusion of 70.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 39.6° C. with apeak area of 25.2 percent. The delta between the DSC Tm and the Tcrystafis 74.1° C.

The DSC curve for the polymer of example 12 shows a peak with a 113.2°C. melting point (Tm) with a heat of fusion of 48.9 J/g. Thecorresponding CRYSTAF curve shows no peak equal to or above 30° C.(Tcrystaf for purposes of further calculation is therefore set at 30°C.). The delta between the DSC Tm and the Tcrystaf is 83.2° C.

The DSC curve for the polymer of example 13 shows a peak with a 114.4°C. melting point (Tm) with a heat of fusion of 49.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 33.8° C. with apeak area of 7.7 percent. The delta between the DSC Tm and the Tcrystafis 84.4° C.

The DSC for the polymer of example 14 shows a peak with a 120.8° C.melting point (Tm) with a heat of fusion of 127.9 J/g. The correspondingCRYSTAF curve shows the tallest peak at 72.9° C. with a peak area of92.2 percent. The delta between the DSC Tm and the Tcrystaf is 47.9° C.

The DSC curve for the polymer of example 15 shows a peak with a 114.3°C. melting point (Tm) with a heat of fusion of 36.2 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 32.3° C. with apeak area of 9.8 percent. The delta between the DSC Tm and the Tcrystafis 82.0° C.

The DSC curve for the polymer of example 16 shows a peak with a 116.6°C. melting point (Tm) with a heat of fusion of 44.9 μg. Thecorresponding CRYSTAF curve shows the tallest peak at 48.0° C. with apeak area of 65.0 percent. The delta between the DSC Tm and the Tcrystafis 68.6° C.

The DSC curve for the polymer of example 17 shows a peak with a 116.0°C. melting point (Tm) with a heat of fusion of 47.0 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 43.1° C. with apeak area of 56.8 percent. The delta between the DSC Tm and the Tcrystafis 72.9° C.

The DSC curve for the polymer of example 18 shows a peak with a 120.5°C. melting point (Tm) with a heat of fusion of 141.8 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 70.0° C. with apeak area of 94.0 percent. The delta between the DSC Tm and the Tcrystafis 50.5° C.

The DSC curve for the polymer of example 19 shows a peak with a 124.8°C. melting point (Tm) with a heat of fusion of 174.8 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 79.9° C. with apeak area of 87.9 percent. The delta between the DSC Tm and the Tcrystafis 45.0° C.

The DSC curve for the polymer of comparative D shows a peak with a 37.3°C. melting point (Tm) with a heat of fusion of 31.6 J/g. Thecorresponding CRYSTAF curve shows no peak equal to and above 30° C. Bothof these values are consistent with a resin that is low in density. Thedelta between the DSC Tm and the Tcrystaf is 7.3° C.

The DSC curve for the polymer of comparative E shows a peak with a124.0° C. melting point (Tm) with a heat of fusion of 179.3 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 79.3° C. with apeak area of 94.6 percent. Both of these values are consistent with aresin that is high in density. The delta between the DSC Tm and theTcrystaf is 44.6° C.

The DSC curve for the polymer of comparative F shows a peak with a124.8° C. melting point (Tm) with a heat of fusion of 90.4 μg. Thecorresponding CRYSTAF curve shows the tallest peak at 77.6° C. with apeak area of 19.5 percent. The separation between the two peaks isconsistent with the presence of both a high crystalline and a lowcrystalline polymer. The delta between the DSC Tm and the Tcrystaf is47.2° C.

Physical Property Testing

Polymer samples are evaluated for physical properties such as hightemperature resistance properties, as evidenced by TMA temperaturetesting, pellet blocking strength, high temperature recovery, hightemperature compression set and storage modulus ratio, G′(25°C.)/G′(100° C.). Several commercially available polymers are included inthe tests: Comparative G* is a substantially linear ethylene/1-octenecopolymer (AFFINITY®, available from The Dow Chemical Company),Comparative H* is an elastomeric, substantially linear ethylene/1-octenecopolymer (AFFINITY®EG8100, available from The Dow Chemical Company),Comparative I is a substantially linear ethylene/1-octene copolymer(AFFINITY® PL1840, available from The Dow Chemical Company), ComparativeJ is a hydrogenated styrene/butadiene/styrene triblock copolymer(KRATON™ G1652, available from KRATON Polymers), Comparative K is athermoplastic vulcanizate (TPV, a polyolefin blend containing dispersedtherein a crosslinked elastomer). Results are presented in Table 4.

TABLE 4 High Temperature Mechanical Properties TMA-1 mm Pellet Blocking300% Strain Compression penetration Strength G′(25° C.)/ Recovery (80°C.) Set (70° C.) Ex. (° C.) lb/ft² (kPa) G′(100° C.) (percent) (percent)D* 51 — 9 Failed — E* 130 — 18 — — F* 70 141 (6.8) 9 Failed 100  5 104 0 (0) 6 81 49  6 110 — 5 — 52  7 113 — 4 84 43  8 111 — 4 Failed 41  997 — 4 — 66 10 108 — 5 81 55 11 100 — 8 — 68 12 88 — 8 — 79 13 95 — 6 8471 14 125 — 7 — — 15 96 — 5 — 58 16 113 — 4 — 42 17 108  0 (0) 4 82 4718 125 — 10 — — 19 133 — 9 — — G* 75 463 (22.2) 89 Failed 100 H* 70 213(10.2) 29 Failed 100 I* 111 — 11 — — J* 107 — 5 Failed 100 K* 152 — 3 —40

In Table 4, Comparative F (which is a physical blend of the two polymersresulting from simultaneous polymerizations using catalyst A1 and B1)has a 1 mm penetration temperature of about 70° C., while Examples 5-9have a 1 mm penetration temperature of 100° C. or greater. Further,examples 10-19 all have a 1 mm penetration temperature of greater than85° C., with most having 1 mm TMA temperature of greater than 90° C. oreven greater than 100° C. This shows that the novel polymers have betterdimensional stability at higher temperatures compared to a physicalblend. Comparative J (a commercial SEBS) has a good 1 mm TMA temperatureof about 107° C., but it has very poor (high temperature 70° C.)compression set of about 100 percent and it also failed to recover(sample broke) during a high temperature (80° C.) 300 percent strainrecovery. Thus the exemplified polymers have a unique combination ofproperties unavailable even in some commercially available, highperformance thermoplastic elastomers.

Similarly, Table 4 shows a low (good) storage modulus ratio, G′(25°C.)/G′(100° C.), for the inventive polymers of 6 or less, whereas aphysical blend (Comparative F) has a storage modulus ratio of 9 and arandom ethylene/octene copolymer (Comparative G) of similar density hasa storage modulus ratio an order of magnitude greater (89). It isdesirable that the storage modulus ratio of a polymer be as close to 1as possible. Such polymers will be relatively unaffected by temperature,and fabricated articles made from such polymers can be usefully employedover a broad temperature range. This feature of low storage modulusratio and temperature independence is particularly useful in elastomerapplications such as in pressure sensitive adhesive formulations.

The data in Table 4 also demonstrate that the polymers of the inventionpossess improved pellet blocking strength. In particular, Example 5 hasa pellet blocking strength of 0 MPa, meaning it is free flowing underthe conditions tested, compared to Comparatives F and G which showconsiderable blocking. Blocking strength is important since bulkshipment of polymers having large blocking strengths can result inproduct clumping or sticking together upon storage or shipping,resulting in poor handling properties.

High temperature (70° C.) compression set for the inventive polymers isgenerally good, meaning generally less than about 80 percent, preferablyless than about 70 percent and especially less than about 60 percent. Incontrast, Comparatives F, G, H and J all have a 70° C. compression setof 100 percent (the maximum possible value, indicating no recovery).Good high temperature compression set (low numerical values) isespecially needed for applications such as gaskets, window profiles,o-rings, and the like.

TABLE 5 Ambient Temperature Mechanical Properties Tensile 100% 300%Retractive Flex Tensile Abrasion: Notched Strain Strain Stress StressModu- Modu- Tensile Elongation Tensile Elongation Volume Tear RecoveryRecovery at 150% Compression Relaxation lus lus Strength at Break¹Strength at Break Loss Strength 21° C. 21° C. Strain Set 21° C. at 50%Ex. (MPa) (MPa) (MPa)¹ (%) (MPa) (%) (mm³) (mJ) (percent) (percent)(kPa) (Percent) Strain² D* 12 5 — — 10 1074 — — 91 83 760 — — E* 895 589— 31 1029 — — — — — — — F* 57 46 — — 12 824 93 339 78 65 400 42 —  5 3024 14 951 16 1116 48 — 87 74 790 14 33  6 33 29 — — 14 938 — — — 75 86113 —  7 44 37 15 846 14 854 39 — 82 73 810 20 —  8 41 35 13 785 14 81045 461 82 74 760 22 —  9 43 38 — — 12 823 — — — — — 25 — 10 23 23 — — 14902 — — 86 75 860 12 — 11 30 26 — — 16 1090 — 976 89 66 510 14 30 12 2017 12 961 13 931 — 1247  91 75 700 17 — 13 16 14 — — 13 814 — 691 91 — —21 — 14 212 160 — — 29 857 — — — — — — — 15 18 14 12 1127  10 1573 —2074  89 83 770 14 — 16 23 20 — — 12 968 — — 88 83 1040  13 — 17 20 18 —— 13 1252 — 1274  13 83 920  4 — 18 323 239 — — 30 808 — — — — — — — 19706 483 — — 36 871 — — — — — — — G* 15 15 — — 17 1000 — 746 86 53 110 2750 H* 16 15 — — 15 829 — 569 87 60 380 23 — I* 210 147 — — 29 697 — — —— — — — J* — — — — 32 609 — — 93 96 1900  25 — K* — — — — — — — — — — —30 — ¹Tested at 51 cm/minute ²measured at 38° C. for 12 hours

Table 5 shows results for mechanical properties for the new polymers aswell as for various comparison polymers at ambient temperatures. It maybe seen that the inventive polymers have very good abrasion resistancewhen tested according to ISO 4649, generally showing a volume loss ofless than about 90 mm³, preferably less than about 80 mm³, andespecially less than about 50 mm³. In this test, higher numbers indicatehigher volume loss and consequently lower abrasion resistance.

Tear strength as measured by tensile notched tear strength of theinventive polymers is generally 1000 mJ or higher, as shown in Table 5.Tear strength for the inventive polymers can be as high as 3000 mJ, oreven as high as 5000 mJ. Comparative polymers generally have tearstrengths no higher than 750 mJ.

Table 5 also shows that the polymers of the invention have betterretractive stress at 150 percent strain (demonstrated by higherretractive stress values) than some of the comparative samples.Comparative Examples F, G and H have retractive stress value at 150percent strain of 400 kPa or less, while the inventive polymers haveretractive stress values at 150 percent strain of 500 kPa (Ex. 11) to ashigh as about 1100 kPa (Ex. 17). Polymers having higher than 150 percentretractive stress values would be quite useful for elastic applications,such as elastic fibers and fabrics, especially nonwoven fabrics. Otherapplications include diaper, hygiene, and medical garment waistbandapplications, such as tabs and elastic bands.

Table 5 also shows that stress relaxation (at 50 percent strain) is alsoimproved (less) for the inventive polymers as compared to, for example,Comparative G. Lower stress relaxation means that the polymer retainsits force better in applications such as diapers and other garmentswhere retention of elastic properties over long time periods at bodytemperatures is desired.

Optical Testing

TABLE 6 Polymer Optical Properties Ex. Internal Haze (percent) Clarity(percent) 45° Gloss (percent) F* 84 22 49 G* 5 73 56  5 13 72 60  6 3369 53  7 28 57 59  8 20 65 62  9 61 38 49 10 15 73 67 11 13 69 67 12 875 72 13 7 74 69 14 59 15 62 15 11 74 66 16 39 70 65 17 29 73 66 18 6122 60 19 74 11 52 G* 5 73 56 H* 12 76 59 I* 20 75 59

The optical properties reported in Table 6 are based on compressionmolded films substantially lacking in orientation. Optical properties ofthe polymers may be varied over wide ranges, due to variation incrystallite size, resulting from variation in the quantity of chainshuttling agent employed in the polymerization.

Extractions of Multi-Block Copolymers

Extraction studies of the polymers of examples 5, 7 and Comparative Eare conducted. In the experiments, the polymer sample is weighed into aglass fritted extraction thimble and fitted into a Kumagawa typeextractor. The extractor with sample is purged with nitrogen, and a 500mL round bottom flask is charged with 350 mL of diethyl ether. The flaskis then fitted to the extractor. The ether is heated while beingstirred. Time is noted when the ether begins to condense into thethimble, and the extraction is allowed to proceed under nitrogen for 24hours. At this time, heating is stopped and the solution is allowed tocool. Any ether remaining in the extractor is returned to the flask. Theether in the flask is evaporated under vacuum at ambient temperature,and the resulting solids are purged dry with nitrogen. Any residue istransferred to a weighed bottle using successive washes of hexane. Thecombined hexane washes are then evaporated with another nitrogen purge,and the residue dried under vacuum overnight at 40° C. Any remainingether in the extractor is purged dry with nitrogen.

A second clean round bottom flask charged with 350 mL of hexane is thenconnected to the extractor. The hexane is heated to reflux with stirringand maintained at reflux for 24 hours after hexane is first noticedcondensing into the thimble. Heating is then stopped and the flask isallowed to cool. Any hexane remaining in the extractor is transferredback to the flask. The hexane is removed by evaporation under vacuum atambient temperature, and any residue remaining in the flask istransferred to a weighed bottle using successive hexane washes. Thehexane in the flask is evaporated by a nitrogen purge, and the residueis vacuum dried overnight at 40° C.

The polymer sample remaining in the thimble after the extractions istransferred from the thimble to a weighed bottle and vacuum driedovernight at 40° C. Results are contained in Table 7.

TABLE 7 ether ether C₈ hexane hexane C₈ residue wt. soluble soluble molesoluble soluble mole C₈ mole Sample (g) (g) (percent) percent¹ (g)(percent) percent¹ percent¹ Comp. 1.097 0.063 5.69 12.2 0.245 22.35 13.66.5 F* Ex. 5 1.006 0.041 4.08 — 0.040 3.98 14.2 11.6 Ex. 7 1.092 0.0171.59 13.3 0.012 1.10 11.7 9.9 ¹Determined by ¹³C NMR

Testing Methods

In the foregoing characterizing disclosure and the examples that follow,the following analytical techniques are employed:

GPC Method for Samples 1-4 and A-C

An automated liquid-handling robot equipped with a heated needle set to160° C. is used to add enough 1,2,4-trichlorobenzene stabilized with 300ppm Ionol to each dried polymer sample to give a final concentration of30 mg/mL. A small glass stir rod is placed into each tube and thesamples are heated to 160° C. for 2 hours on a heated, orbital-shakerrotating at 250 rpm. The concentrated polymer solution is then dilutedto 1 mg/ml using the automated liquid-handling robot and the heatedneedle set to 160° C.

A Symyx Rapid GPC system is used to determine the molecular weight datafor each sample. A Gilson 350 pump set at 2.0 ml/min flow rate is usedto pump helium-purged 1,2-dichlorobenzene stabilized with 300 ppm Ionolas the mobile phase through three Plgel 10 micrometer (μm) Mixed B 300mm×7.5 mm columns placed in series and heated to 160° C. A Polymer LabsELS1000 Detector is used with the Evaporator set to 250° C., theNebulizer set to 165° C., and the nitrogen flow rate set to 1.8 SLM at apressure of 60-80 psi (400−600 kPa) N2. The polymer samples are heatedto 160° C. and each sample injected into a 250 μl loop using theliquid-handling robot and a heated needle. Serial analysis of thepolymer samples using two switched loops and overlapping injections areused. The sample data is collected and analyzed using Symyx Epoch™software. Peaks are manually integrated and the molecular weightinformation reported uncorrected against a polystyrene standardcalibration curve.

The DSC melting peak is measured as the maximum in heat flow rate (W/g)with respect to the linear baseline drawn between −30° C. and end ofmelting. The heat of fusion is measured as the area under the meltingcurve between −30° C. and the end of melting using a linear baseline.

Standard CRYSTAF Method

Branching distributions are determined by crystallization analysisfractionation (CRYSTAF) using a CRYSTAF 200 unit commercially availablefrom PolymerChar, Valencia, Spain. The samples are dissolved in 1,2,4trichlorobenzene at 160° C. (0.66 mg/mL) for 1 hr and stabilized at 95°C. for 45 minutes. The sampling temperatures range from 95 to 30° C. ata cooling rate of 0.2° C./min. An infrared detector is used to measurethe polymer solution concentrations. The cumulative solubleconcentration is measured as the polymer crystallizes while thetemperature is decreased. The analytical derivative of the cumulativeprofile reflects the short chain branching distribution of the polymer.

The CRYSTAF peak temperature and area are identified by the peakanalysis module included in the CRYSTAF Software (Version 2001.b,PolymerChar, Valencia, Spain). The CRYSTAF peak finding routineidentifies a peak temperature as a maximum in the dW/dT and the areabetween the largest positive inflections on either side of theidentified peak in the derivative curve. To calculate the CRYSTAF curve,the preferred processing parameters are with a temperature limit of 70°C. and with smoothing parameters above the temperature limit of 0.1, andbelow the temperature limit of 0.3.

DSC Standard Method (Excluding Samples 1-4 and A-C)

Differential Scanning Calorimetry results are determined using a TAImodel Q1000 DSC equipped with an RCS cooling accessory and anautosampler. A nitrogen purge gas flow of 50 ml/min is used. The sampleis pressed into a thin film and melted in the press at about 175° C. andthen air-cooled to room temperature (25° C.). 3-10 mg Of material isthen cut into a 6 mm diameter disk, accurately weighed, placed in alight aluminum pan (ca 50 mg), and then crimped shut. The thermalbehavior of the sample is investigated with the following temperatureprofile. The sample is rapidly heated to 180° C. and held isothermal for3 minutes in order to remove any previous thermal history. The sample isthen cooled to −40° C. at 10° C./min cooling rate and held at −40° C.for 3 minutes. The sample is then heated to 150° C. at 10° C./min.heating rate. The cooling and second heating curves are recorded.

The DSC melting peak is measured as the maximum in heat flow rate (W/g)with respect to the linear baseline drawn between −30° C. and end ofmelting. The heat of fusion is measured as the area under the meltingcurve between −30° C. and the end of melting using a linear baseline.

Abrasion Resistance

Abrasion resistance is measured on compression molded plaques accordingto ISO 4649. The average value of 3 measurements is reported. Plaquesfor the test are 6.4 mm thick and compression molded using a hot press(Carver Model #4095-4PR1001R). The pellets are placed betweenpolytetrafluoroethylene sheets, heated at 190° C. at 55 psi (380 kPa)for 3 minutes, followed by 1.3 MPa for 3 minutes, and then 2.6 MPa for 3minutes. Next the plaques are cooled in the press with running coldwater at 1.3 MPa for 1 minute and removed for testing.

GPC Method (For All Samples, Including AA-DD, but Excluding Samples 1-4and A-C)

The gel permeation chromatographic system consists of either a PolymerLaboratories Model PL-210 or a Polymer Laboratories Model PL-220instrument. The column and carousel compartments are operated at 140° C.Three Polymer Laboratories 10-micron Mixed-B columns are used. Thesolvent is 1,2,4 trichlorobenzene. The samples are prepared at aconcentration of 0.1 grams of polymer in 50 milliliters of solventcontaining 200 ppm of butylated hydroxytoluene (BHT). Samples areprepared by agitating lightly for 2 hours at 160° C. The injectionvolume used is 100 microliters and the flow rate is 1.0 ml/minute.

Calibration of the GPC column set is performed with 21 narrow molecularweight distribution polystyrene standards with molecular weights rangingfrom 580 to 8,400,000, arranged in 6 “cocktail” mixtures with at least adecade of separation between individual molecular weights. The standardsare purchased from Polymer Laboratories (Shropshire, UK). Thepolystyrene standards are prepared at 0.025 grams in 50 milliliters ofsolvent for molecular weights equal to or greater than 1,000,000, and0.05 grams in 50 milliliters of solvent for molecular weights less than1,000,000. The polystyrene standards are dissolved at 80° C. with gentleagitation for 30 minutes. The narrow standards mixtures are run firstand in order of decreasing highest molecular weight component tominimize degradation. The polystyrene standard peak molecular weightsare converted to polyethylene molecular weights using the followingequation (as described in Williams and Ward, J. Polym. Sci., Polym Let.,6, 621 (1968)): Mpolyethylene=0.431(Mpolystyrene).

Polyetheylene equivalent molecular weight calculations are performedusing Viscotek TriSEC software Version 3.0.

Compression Set

Compression set is measured according to ASTM D 395. The sample isprepared by stacking 25.4 mm diameter round discs of 3.2 mm, 2.0 mm, and0.25 mm thickness until a total thickness of 12.7 mm is reached. Thediscs are cut from 12.7 cm×12.7 cm compression molded plaques moldedwith a hot press under the following conditions: zero pressure for 3 minat 190° C., followed by 86 MPa for 2 min at 190° C., followed by coolinginside the press with cold running water at 86 MPa.

Density

Samples for density measurement are prepared according to ASTM D 1928.Measurements are made within one hour of sample pressing using ASTMD792, Method B.

Flexural/Secant Modulus/Storage Modulus

Samples are compression molded using ASTM D 1928. Flexural and 2 percentsecant moduli are measured according to ASTM D-790. Storage modulus ismeasured according to ASTM D 5026-01 or equivalent technique.

Optical Properties

Films of 0.4 mm thickness are compression molded using a hot press(Carver Model #4095-4PR1001R). The pellets are placed betweenpolytetrafluoroethylene sheets, heated at 190° C. at 55 psi (380 kPa)for 3 min, followed by 1.3 MPa for 3 min, and then 2.6 MPa for 3 min.The film is then cooled in the press with running cold water at 1.3 MPafor 1 min. The compression molded films are used for opticalmeasurements, tensile behavior, recovery, and stress relaxation.

Clarity is measured using BYK Gardner Haze-gard as specified in ASTM D1746.

45° gloss is measured using BYK Gardner Glossmeter Microgloss 45° asspecified in ASTM D-2457.

Internal haze is measured using BYK Gardner Haze-gard based on ASTM D1003 Procedure A. Mineral oil is applied to the film surface to removesurface scratches.

Mechanical Properties—Tensile, Hysteresis, and Tear

Stress-strain behavior in uniaxial tension is measured using ASTM D 1708microtensile specimens. Samples are stretched with an Instron at 500%min-1 at 21° C. Tensile strength and elongation at break are reportedfrom an average of 5 specimens.

100%, 150%, and 300% Hysteresis are determined from cyclic loading to100%, 150%, and 300% strains using ASTM D 1708 microtensile specimenswith an Instron™ instrument. The sample is loaded and unloaded at 267%min-1 for 3 cycles at 21° C. Cyclic experiments at 300% and 80° C. areconducted using an environmental chamber. In the 80° C. experiment, thesample is allowed to equilibrate for 45 minutes at the test temperaturebefore testing. In the 21° C., 300% strain cyclic experiment, theretractive stress at 150% strain from the first unloading cycle isrecorded. Percent recovery for all experiments are calculated from thefirst unloading cycle using the strain at which the load returned to thebase line. The percent recovery is defined as:

${\% \mspace{14mu} {Recovery}} = {\frac{ɛ_{f} - ɛ_{s}}{ɛ_{f}} \times 100}$

where ε_(f) is the strain taken for cyclic loading and ε_(s) is thestrain where the load returns to the baseline during the 1st unloadingcycle. Permanent set is defined as ε_(s).

Stress relaxation is measured at 50 percent strain and 37° C. for 12hours using an Instron™ instrument equipped with an environmentalchamber. The gauge geometry was 76 mm×25 mm×0.4 mm. After equilibratingat 37° C. for 45 min in the environmental chamber, the sample wasstretched to 50% strain at 333% min-1. Stress was recorded as a functionof time for 12 hours. The percent stress relaxation after 12 hours wascalculated using the formula:

${\% \mspace{14mu} {Stress}\mspace{14mu} {Relaxation}} = {\frac{L_{0} - L_{12}}{L_{0}} \times 100}$

where L0 is the load at 50% strain at 0 time and L12 is the load at 50percent strain after 12 hours.

Tensile notched tear experiments are carried out on samples having adensity of 0.88 g/cc or less using an Instron™ instrument. The geometryconsists of a gauge section of 76 mm×13 mm×0.4 mm with a 2 mm notch cutinto the sample at half the specimen length. The sample is stretched at508 mm min-1 at 21° C. until it breaks. The tear energy is calculated asthe area under the stress-elongation curve up to strain at maximum load.An average of at least 3 specimens are reported.

TMA

Thermal Mechanical Analysis (Penetration Temperature) is conducted on 30mm diameter×3.3 mm thick, compression molded discs, formed at 180° C.and 10 MPa molding pressure for 5 minutes and then air quenched. Theinstrument used is a TMA 7, brand available from Perkin-Elmer. In thetest, a probe with 1.5 mm radius tip (P/N N519-0416) is applied to thesurface of the sample disc with 1N force. The temperature is raised at5° C./min from 25° C. The probe penetration distance is measured as afunction of temperature. The experiment ends when the probe haspenetrated 1 mm into the sample.

DMA

Dynamic Mechanical Analysis (DMA) is measured on compression moldeddisks formed in a hot press at 180° C. at 10 MPa pressure for 5 minutesand then water cooled in the press at 90° C./min. Testing is conductedusing an ARES controlled strain rheometer (TA instruments) equipped withdual cantilever fixtures for torsion testing.

A 1.5 mm plaque is pressed and cut in a bar of dimensions 32×12 mm. Thesample is clamped at both ends between fixtures separated by 10 mm (gripseparation □L) and subjected to successive temperature steps from −100°C. to 200° C. (5° C. per step). At each temperature the torsion modulusG′ is measured at an angular frequency of 10 rad/s, the strain amplitudebeing maintained between 0.1 percent and 4 percent to ensure that thetorque is sufficient and that the measurement remains in the linearregime.

An initial static force of 10 g is maintained (auto-tension mode) toprevent slack in the sample when thermal expansion occurs. As aconsequence, the grip separation □L increases with the temperature,particularly above the melting or softening point of the polymer sample.The test stops at the maximum temperature or when the gap between thefixtures reaches 65 mm.

Pellet Blocking Strength

Pellets (150 g) are loaded into a 2″ (5 cm) diameter hollow cylinderthat is made of two halves held together by a hose clamp. A 2.75 lb(1.25 kg) load is applied to the pellets in the cylinder at 45° C. for 3days. After 3 days, the pellets loosely consolidate into a cylindricalshaped plug. The plug is removed from the form and the pellet blockingforce measured by loading the cylinder of blocked pellets in compressionusing an Instron™ instrument to measure the compressive force needed tobreak the cylinder into pellets.

Melt Index

Melt index, or 12, is measured in accordance with ASTM D 1238, Condition190° C./2.16 kg. Melt index, or 110 is also measured in accordance withASTM D 1238, Condition 190° C./10 kg.

ATREF

Analytical temperature rising elution fractionation (ATREF) analysis isconducted according to the method described in U.S. Pat. No. 4,798,081.The composition to be analyzed is dissolved in trichlorobenzene andallowed to crystallize in a column containing an inert support(stainless steel shot) by slowly reducing the temperature to 20° C. at acooling rate of 0.1° C./min. The column is equipped with an infrareddetector. An ATREF chromatogram curve is then generated by eluting thecrystallized polymer sample from the column by slowly increasing thetemperature of the eluting solvent (trichlorobenzene) from 20 to 120° C.at a rate of 1.5° C./min.

Polymer Fractionation by TREF

Large-scale TREF fractionation is carried by dissolving 15-20 g ofpolymer in 2 liters of 1,2,4-trichlorobenzene (TCB) by stirring for 4hours at 160° C. The polymer solution is forced by 15 psig (100 kPa)nitrogen onto a 3 inch by 4 foot (7.6 cm×12 cm) steel column packed witha 60:40 (v:v) mix of 30-40 mesh (600-425 μm) spherical, technicalquality glass beads (available from Potters Industries, HC 30 Box 20,Brownwood, Tex., 76801) and stainless steel, 0.028″ (0.7 mm) diametercut wire shot (available form Pellets, Inc. 63 Industrial Drive, NorthTonawanda, N.Y., 14120). The column is immersed in a thermallycontrolled oil jacket, set initially to 160° C. The column is firstcooled ballistically to 125° C., then slow cooled to 20° C. at 0.04° C.per minute and held for one hour. Fresh TCB is introduced at about 65ml/min while the temperature is increased at 0.167° C. per minute.

Approximately 2000 ml portions of eluant from the preparative TREFcolumn are collected in a 16 station, heated fraction collector. Thepolymer is concentrated in each fraction using a rotary evaporator untilabout 50 to 100 ml of the polymer solution remains. The concentratedsolutions are allowed to stand overnight before adding excess methanol,filtering, and rinsing (approx. 300-500 ml of methanol including thefinal rinse). The filtration step is performed on a 3 position vacuumassisted filtering station using 5.0 μm polytetrafluoroethylene coatedfilter paper (available from Osmonics Inc., Cat# Z50WP04750). Thefiltrated fractions are dried overnight in a vacuum oven at 60° C. andweighed on an analytical balance before further testing.

13C NMR Analysis

The samples are prepared by adding approximately 3 g of a 50/50 mixtureof tetrachloroethane-d2/orthodichlorobenzene to 0.4 g sample in a 10 mmNMR tube. The samples are dissolved and homogenized by heating the tubeand its contents to 150° C. The data is collected using a JEOL Eclipse™400 MHz spectrometer or a Varian Unity Plus™ 400 MHz spectrometer,corresponding to a 13C resonance frequency of 100.5 MHz. The data isacquired using 4000 transients per data file with a 6 second pulserepetition delay. To achieve minimum signal-to-noise for quantitativeanalysis, multiple data files are added together. The spectral width is25,000 Hz with a minimum file size of 32K data points. The samples areanalyzed at 130° C. in a 10 mm broad band probe. The comonomerincorporation is determined using Randall's triad method (Randall, J.C.; JMS-Rev. Macromol. Chem. Phys., C29, 201-317 (1989).

Atomic Force Microscopy (AFM)

Sections are collected from the sample material using a Leica UCT™microtome with a FC cryo-chamber operated at −80° C. A diamond knife isused to section all sample material to a thickness of 120 nm. Sectionsare placed on freshly cleaved mica surfaces, and mounted on standard AFMspecimen metal support disks with a double carbon tape. The sections areexamined with a DI NanoScope IV™ Multi-Mode AFM, in tapping mode withphase detection. Nano-sensor tips are used in all experiments.

For nonwoven laminate structures, the following tensile test is used:

For the tensile test, 6 inch by 1 inch specimens can be cut from thesamples. When appropriate, a direction such as machine direction (MD) orcross direction (CD) may be specified for samples which possessdirectionality due to the particular nature of the manufacturingprocess. These specimens can be then loaded into an Instron 5564(Canton, Mass.) equipped with pneumatic grips and fitted with a 20 poundcapacity tension load cell or a higher capacity load cell when loadsexceed 20 pounds. After proper calibration of the load cell according tothe manufacturer's instructions, the specimen is oriented parallel tothe displacement direction of the crosshead and then gripped with aseparation of 3 inches. The sample is then stretched to break at a rateof 500% per minute (111.25 mm/min). Strain or elongation is a quantitythat is commonly used. It is described according to the followingequation:

${{Elongation}(\%)} = {\frac{L - L_{0}}{L_{0}} \times 100\%}$

such that L_(o) is defined as the original length of 3 inches, L is thelength of the sample at any point during the tensile test. The length ofthe sample and the corresponding force at the point just before completebreakage of the sample is noted. This point may or may not correspond toa local maximum in force. This point is also commonly described aselongation at break or strain at break.

For cast film, preferably the melt index of at least one layer,preferably the low crystallinity layer, is at least 1 g/10 min and morepreferably from 2 to 20 g/10 min. For blown film, preferably at leastone layer, preferably the low crystallinity layer, have melt indices ofless than 5 g/10 min and more preferably less than 2 g/10 min. and aslow as about 0.1 g/10 min.

The Article

One embodiment of the invention includes an article comprising a lowcrystallinity layer and a high crystallinity layer, the highcrystallinity layer is often capable of undergoing plastic deformationupon elongation. “Elongation” is a uni-axial or biaxial stretching ofthe article to a degree sufficient to cause plastic deformation of thehigh crystallinity layer. Dimensional profile (surface roughness orcorrugated-like structure) and increase in Haze value can be used by oneof ordinary skill in the art to determine whether an article isplastically deformed. Haze is measured according to ASTM D1003 using aHazeGard PLUS Hazemeter available from BYK Gardner of Melville, N.Y.,with a light source CIE Illuminant C. Plastically deformed articlesaccording to the invention can have a Haze value of greater than about70%, or greater than about 80%, or greater than about 90%. Theplastically deformed articles have an increased haze value compared tothe article prior to elongation. Though not limited by theory, thechange (increase) in haze is thought to originate from an increase insurface roughness. Surface roughness is thought to originate fromdifferential recovery behavior after deformation. Upon deformation, thehigh and low crystallinity layers are thought to extend similarly butupon release, there is differential recovery behavior between the higherand lower crystallinity layers. Lower recovery (higher set) of thehigher crystallinity layer and the retractive force of the lowercrystallinity layer is thought to produce a mechanical instability andresult in a structure that can be described as corrugated,micro-undulated, micro-textured, or crenulated.

The surface roughness of the article can be measured by a number ofinstruments capable of precise surface roughness measurements. One suchinstrument is Surfcom 110B manufactured by Tokyo Seimitsu Company. TheSurfcom instrument contains a diamond stylus which moves across thesurface of the sample. The sample can range in hardness from metal toplastic to rubber. The instrument records the surface irregularitiesover the length traveled by the stylus. The surface roughness isquantified using a combination of three factors Ra (pm)—the arithmeticmean representing the departure of the extrudate surface profile from amean line; Ry (m)—the sum of the height of the highest peak from a meanline and the depth of the deepest valley from a mean line; and Rz(um)—the sum of two means which are the average height of the fivehighest peaks from a mean line and the average depth of the five deepestvalleys from a mean line. The combination of the Ra, Ry and Rz valuescharacterize the surface profile of the film. By comparing the values ofthe non-elongated film against the values of the plastically deformedfilm, the increase in the roughness of the film surface, and thus theeffectiveness of the orientation process, can be determined.

A pre-stretching or elongating step is optional, but preferable, and maybe done on the article, one or more individual layers of the articlesuch as the high crystallinity layer, the low crystallinity layer, orboth, or may not be done at all. If being done to more than one layer,the pre-stretching may be done on each layer separately or on the layerstogether. Similarly, the stretching may be done in any direction.

In some embodiments, the article is elongated in at least one directionto at least about 100%, or at least about 150%, of its original lengthor width. Generally, the article is elongated at a temperature below themelting temperature of either of the low crystallinity polymer or highcrystallinity polymer. This “pre-stretching” step is accomplished by anymeans known to those skilled in the art, especially however, they areparticularly suited for MD (machine direction) and/or CD (crossdirection) orientation activation methods including ring-rolling, MDorientation (MDO) rolls, etc., and a stretch-bonded lamination process.This stretching is a “pre-stretch” in the context that the film willagain be likely stretched in its ultimate use, e.g., packaging orshipping applications, and diapers. This step may be performed on thearticles of invention alone or on the articles of invention in laminateform or on some other form such as elastic nonwovens.

The article prior to being pre-stretched may have poor elastic andhysteresis characteristics due to the influence of the highcrystallinity layer(s). However, upon elongating the article beyond theplastic deformation point of the high crystallinity layer(s), theelastic and hysteresis properties are improved, e.g., the effect ofpre-stretching films above 50% strain results in subsequent lowerpermanent set.

Typically the article is formed using any fabrication process, such asan extrusion coated or cast film process, lamination processes, meltblown, spunbond, fiber extrusion, fiber spinning processes, separated orrecovered from that process, and then pre-stretched. Preferably thearticle is pre-stretched after the article has solidified (morepreferably, but not necessarily, crystallized). Operating at or abovethe melting point of the lower crystallinity layer is not favored forthis invention as is typical, for example, in the double bubbleorientation (Pahlke) process, and because generally it will not producethe desired structures. Preferably, the lower crystallinity layer hassubstantially achieved its maximum crystallinity before the pre-stretchprocedure.

This invention is especially useful for film converters who must storethe elastic film on rolls prior to assembly into laminate structures. Aparticular challenge for conventional elastic film is blocking. Thisinvention serves to remedy this problem. This invention is also usefulduring conversion to reduce the coefficient of friction and to increasethe bending stiffness of the film during conveyance, cutting, assembly,and other steps. Other applications include elastic diaper back-sheets,feminine hygiene films, elastic strips, elastic laminates in gowns,sheets and the like.

In one particular embodiment, the article is formed by co-extruding thelow crystallinity layer and high crystallinity layer prior toelongation. The article can optionally be oriented in the machinedirection (MD) or the transverse direction (TD) or both directions(biaxially) using conventional equipment and processes. Orientation canbe carried in a separate step prior to the elongation step describedbelow. Thus, an oriented article can be prepared as an intermediateproduct, which is then later elongated in a separate step. In thisembodiment, the orientation is preferably carried out such that minimalplastic deformation of the high crystallinity layer occurs.Alternatively, orientation and elongation to plastic deformation can becarried out in a single step.

In some embodiments the low crystallinity layer is in contact orintimate contact with the high crystallinity layer. The term “incontact” means that there is sufficient interfacial adhesion providedby, for example, compatible crystallinity, such that adjacent polymericlayers do not delaminate, even after orientation and/or elongation. Theterm “in intimate contact” means that essentially one full planarsurface of one layer is in an adhering relationship with a planarsurface of another layer. Typically the two planar surfaces areco-terminus with one another. In certain embodiments the lowcrystallinity layer adheres to the high crystallinity layer through theuse of conventional materials, such as adhesives.

“Planar surface” is used in distinction to “edge surface”. Ifrectangular in shape or configuration, a film will comprise two opposingplanar surfaces joined by four edge surfaces (two opposing pairs of edgesurfaces, each pair intersecting the other pair at right angles). Thebottom planar surface of the first skin layer is adapted to join oradhere to the top planar surface of the core layer, and the top planarsurface of the second skin layer is adapted to join or adhere to thebottom planar surface of the core layer. In practice, the first andsecond skin layers are typically of the same composition and as such,are interchangeable. Likewise, the top and bottom planar surfaces ofboth the skin and core layers are functionally essentially the same andas such, each layer can be “flipped”, i.e., the top planar surface canserve as the bottom planar surface, and vice versa. The films can be ofany size and shape and as such, so can the planar and edge surfaces,e.g., thin or thick, polygonal or circular, etc. Typically, the film isin an extended ribbon form.

The films of this invention can be prepared by any conventional process,and often are formed by separately extruding the individual layers usingconventional extrusion equipment, and then joining or laminating therespective planar surfaces of the individual layers to one another usingconventional techniques and equipment, e.g., feeding the individuallayers together in an aligned fashion through a set of pinch rollers.

The skin layers typically comprise less than 30 weight percent (wt %),preferably less than 20 wt % and more preferably less than 10 wt %, of athree-layer film consisting of one core layer and two skin layers. Eachskin layer is typically the same as the other skin layer in thicknessand weight although one skin layer can vary from the other in either orboth measurements.

In another embodiment the article is a film wherein the highcrystallinity layer forms a skin layer. In a different embodiment, thehigh crystallinity layer is intermediate to the low crystallinity layerand another type of skin layer, such as any conventional polymer layer.In yet another embodiment, high crystallinity layers are present on bothsides of the low crystallinity layer. In this embodiment, the two highcrystallinity layers can be the same or different in composition and thesame or different in thickness. In yet another embodiment, the articleincludes, in sequence, a high crystallinity layer, a low crystallinitylayer, and an additional low crystallinity layer. In this embodiment,the two low crystallinity layers can be the same or different incomposition and the same or different in thickness. The article cancomprise as many layers as desired.

The high crystallinity layer or one or more low crystallinity layers mayalso form a skin layer and be adapted to adhere by melting onto asubstrate. Skin layers other than the high crystallinity and lowcrystallinity layer can also be adapted for melt adhesion onto asubstrate.

Non-polymeric additives that can be added to one or more layers include,process oil, flow improvers, fire retardants, antioxidants,plasticizers, pigments, vulcanizing or curative agents, vulcanizing orcurative accelerators, cure retarders, processing aids, flameretardants, tackifying resins, and the like. These compounds may includefillers and/or reinforcing materials. These include carbon black, clay,talc, calcium carbonate, mica, silica, silicate, and combinations of twoor more of these materials. Other additives, which may be employed toenhance properties, include anti-blocking and coloring agents.Lubricants, mold release agents, nucleating agents, reinforcements, andfillers (including granular, fibrous, or powder-like) may also beemployed. Nucleating agents and fillers tend to improve rigidity of thearticle. The exemplary lists provided above are not exhaustive of thevarious kinds and types of additives that can be employed with thepresent invention.

The overall thickness of the article is not particularly limited, but istypically less than 20 mil, often less than 10 mil. The thickness of anyof the individual layers can vary widely, and are typically determinedby process, use and economic considerations.

Low Crystallinity Layer

The low crystallinity layer has a level of crystallinity that can bedetected by Differential Scanning Calorimetry (DSC), but it haselastomeric properties. The low crystallinity layer does not havesubstantial loss of its elastic properties, even after extension of thehigh crystallinity layer to and beyond the point of plastic deformation.The low crystallinity layer often comprises a low crystallinity polymerand, optionally, at least one additional polymer. Typically, the lowcrystallinity layer(s) comprises at least about 40, preferably at leastabout 50, more preferably at least about 60, preferably at least about80 and up to about 98 weight percent of the total weight of the high andlow crystallinity polymers.

Low Crystallinity Polymer

The low crystallinity polymer of the present invention is a soft,elastic polymer that often has a low to moderate level of crystallinity.In a particular embodiment, the low crystallinity polymer is anethylene/α-olefin multi-block interpolymers employed in the presentinvention are a unique class of compounds that are further defined anddiscussed in copending PCT Application No. PCT/US2005/008917, filed onMar. 17, 2005 and published on Sep. 29, 2005 as WO/2005/090427, which inturn claims priority to U.S. Provisional Application No. 60/553,906,filed Mar. 17, 2004. The low crystallinity polymer may also be acopolymer of propylene and one or more comonomers selected fromethylene, C4-C12 alpha-olefins, and combinations of two or more suchcomonomers. In a particular aspect of this embodiment, the lowcrystallinity polymer includes units derived from the one or morecomonomers in an amount ranging from a lower limit of about 2%, 5%, 6%,8%, or 10% by weight to an upper limit of about 60%, 50%, or 45% byweight. These percentages by weight are based on the total weight of theethylene-derived and comonomer-derived units, i.e., based on the sum ofweight percent ethylene-derived units and weight percentcomonomer-derived units equaling 100%.

Embodiments of the invention include low crystallinity polymers having aheat of fusion, as determined by DSC, ranging from a lower limit ofabout 1 Joules/gram (J/g), or 3 J/g, or 5 J/g, or 10 J/g, or 15 J/g, toan upper limit of about 125 J/g, or 100 J/g, or 75 J/g, or 57 J/g, or 50J/g, or 47 J/g, or 37 J/g, or 30 J/g. “Heat of fusion” is measured usingDSC.

The crystallinity of the low crystallinity polymer may also be expressedin terms of crystallinity percent. The thermal energy for 100%crystalline polypropylene is taken to be 165 J/g., and for 100%crystalline polyethylene is 292 J/gm. That is, 100% crystallinity istaken as being equal to 165 J/g for polypropylene and 292 J/gm forpolyethylene.

The level of crystallinity may be reflected in the melting point.“Melting point” is determined by DSC as previously discussed. The lowcrystallinity polymer, according to an embodiment of the invention hasone or more melting points. The peak having the highest heat flow (i.e.,tallest peak height) of these peaks is considered the melting point. Thelow crystallinity polymer can have a melting point determined by DSCranging from an upper limit of about 135 C, or 130 C, to a lower limitof about 20 C, or 25 C, or 30 C, or 35 C, or 40 C or 45 C. The lowcrystallinity polymer can have a crystallization peak temperaturedetermined by DSC ranging from an upper limit of about 120 C, or 110 C,to a lower limit of about 0 C, 30 C, or 50 C, or 60 C.

The low crystallinity polymer can have a weight average molecular weight(Mw) of from about 10,000 to about 5,000,000 g/mol, or from about 20,000to about 1,000,000 g/mol, or from about 80,000 to about 500,000 g/moland a molecular weight distribution Mw/Mn (MWD), sometimes referred toas a “polydispersity index” (PDI), ranging from a lower limit of about1.5 or 1.8 to an upper limit of about 40 or 20 or 10 or 5 or 3.

In some embodiments of the invention, the low crystallinity polymer hasa Mooney viscosity ML(1+4)125 C of about 100 or less, or 75 or less, orless, or 30 or less. Mooney viscosity is measured as ML(1+4)125° C.according to ASTM D1646 unless otherwise specified.

Additional Polymers

In some embodiments, the low crystallinity layer optionally comprisesone or more additional polymers. The optional additional polymer can bethe same or different from the high crystallinity polymer of the highcrystallinity layer. In a particular embodiment, the additional polymerhas a crystallinity between the crystallinity of the low crystallinitypolymer and the high crystallinity polymer.

In a particular embodiment, the low crystallinity layer is a blendcomprising a continuous phase including the low crystallinity polymerdescribed above and a dispersed phase including a relatively morecrystalline additional polymer. Minor amounts of the additional polymermay be present in the continuous phase. In a particular aspect of thisembodiment, the dispersed phase is composed of individual domains lessthan 50 microns in diameter. In some embodiments, these individualdomains of the dispersed phase can be maintained during processing evenwithout cross-linking.

In one embodiment, the additional polymer is a propylene copolymer ofethylene, a C4-C20 α-olefin, or combinations thereof, wherein the amountof ethylene and/or C4-C20 α-olefin(s) present in the additional polymeris less than the amount of ethylene and/or C4-C20 α-olefin(s) present inthe low crystallinity polymer.

In one embodiment, the low crystallinity layer is a blend comprisingfrom about 2% to about 95% by weight of an additional polymer and fromabout 5% to about 98% by weight of the low crystallinity polymer basedon the total weight of the blend, in which the additional polymer ismore crystalline than the low crystallinity polymer. In a particularaspect of this embodiment, the additional polymer is present in theblend in an amount of from a lower limit of about 2% or 5% to an upperlimit of about 30% or 20% or 15% by weight based on the total weight ofthe blend.

High Crystallinity Layer

The high crystallinity layer has a level of crystallinity sufficient topermit yield and plastic deformation during elongation and/or to havenon-tacky or non-blocky characteristics. The high crystallinity layercan be oriented in the machine, cross (transverse) or oblique directiononly, or in two or more of these directions as can be detected bymicroscopy. The orientation can lead to subsequent frangibility of thehigh crystallinity layer. Typically, the high crystallinity layer(s)comprises less than about 60, preferably less than about 50, morepreferably less than about 40, and can be as low as about 2 weightpercent of the total weight of the high and low crystallinity layers.

High Crystallinity Polymer

The high crystallinity layer often includes a high crystallinitypolymer. The high crystallinity polymers of the present invention aredefined as polymeric components, including blends, that includehomopolymers or copolymers of ethylene or propylene or an alpha-olefinhaving 12 carbon atoms or less with minor olefinic monomers that includelinear, branched, or ring-containing C3 to C30 olefins, capable ofinsertion polymerization, or combinations of such olefins. In oneembodiment, the amount of alpha-olefin in the copolymer has an upperrange of about 9 wt %, or 8 wt %, or 6 wt %, and a lower range of about2 wt %, based on the total weight of the high crystallinity polymer.

Examples of minor olefinic monomers include, but are not limited to C2to C20 linear or branched alpha-olefins, such as ethylene, propylene,1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-pentene,and 3,5,5-trimethyl-1-hexene, and ring-containing olefinic monomerscontaining up to 30 carbon atoms such as cyclopentene, vinylcyclohexane,vinylcyclohexene, norbornene, and methyl norbornene.

Suitable aromatic-group-containing monomers can contain up to 30 carbonatoms and can comprise at least one aromatic structure, such as aphenyl, indenyl, fluorenyl, or naphthyl moiety. Thearomatic-group-containing monomer further includes at least onepolymerizable double bond such that after polymerization, the aromaticstructure will be pendant from the polymer backbone. The polymerizableolefinic moiety of the aromatic-group containing monomer can be linear,branched, cyclic-containing, or a mixture of these structures. When thepolymerizable olefinic moiety contains a cyclic structure, the cyclicstructure and the aromatic structure can share 0, 1, or 2 carbons. Thepolymerizable olefinic moiety and/or the aromatic group can also havefrom one to all of the hydrogen atoms substituted with linear orbranched alkyl groups containing from 1 to 4 carbon atoms. Examples ofaromatic monomers include, but are not limited to styrene,alpha-methylstyrene, vinyltoluenes, vinylnaphthalene, allyl benzene, andindene, especially styrene and allyl benzene.

In one embodiment, the high crystallinity polymer is a homopolymer orcopolymer of polypropylene with isotactic propylene sequences ormixtures of such sequences. The polypropylene used can vary widely inform. The propylene component may be a combination of homopolymerpolypropylene, and/or random, and/or block copolymers. In a particularembodiment, the high crystallinity polymer is copolymer of propylene andone or more comonomers selected from ethylene and C4 to C12 α-olefins.In a particular aspect of this embodiment, the comonomer is present inthe copolymer in an amount of up to about 9% by weight, or from about 2%to about 8% by weight, or from about 2% to about 6% by weight, based onthe total weight of the copolymer.

In another embodiment, the high crystallinity polymer is a homopolymeror copolymer of ethylene and one or more comonomers selected from C3 toC20 α-olefins. In a particular aspect of this embodiment, the comonomeris present in the copolymer in an amount of from about 0.5 wt % to about25 wt % based on the total weight of the copolymer.

In certain embodiments of the invention, the high crystallinity polymerhas a weight average molecular weight (Mw) of from about10,000-5,000,000 g/mol, or from about 20,000-1,000,000 g/mol, or fromabout 80,000-500,000 gμmol and a molecular weight distribution Mw/Mn(sometimes referred to as a “polydispersity index” (PDI)) ranging from alower limit of about 1.5-1.8 to an upper limit of about 40 or 20 or 10or 5 or 3.

In one embodiment, the high crystallinity polymer is produced withmetallocene catalysis and displays narrow molecular weight distribution,meaning that the ratio of the weight average molecular weight to thenumber average molecular weight will be equal to or below about 4, mosttypically in the range of from about 1.7-4.0, preferably from about1.8-2.8.

In another embodiment, the high crystallinity polymer is produced with asingle site catalysis, although non-metallocene, and displays narrowmolecular weight distribution, meaning that the ratio of the weightaverage molecular weight to the number average molecular weight will beequal to or below about 4, most typically in the range of from about1.7-4.0, preferably from about 1.8-2.8.

In another embodiment, the high crystallinity polymer is produced with aZiegler-Natta or chrome catalysis, and displays medium to broadmolecular weight distribution, meaning that the ratio of the weightaverage molecular weight to the number average molecular weight will beequal to or below about 60, most typically in the range of from about3.5-20, preferably from about 3.5-8.

The high crystallinity polymers of the present invention can optionallycontain long chain branches. These can optionally be generated using oneor more □,□-dienes. Alternatively, the high crystallinity polymer maycontain small quantities of at least one diene, and preferably at leastone of the dienes is a non-conjugated diene to aid in the vulcanizationor other chemical modification. The amount of diene is preferably nogreater than about 10 wt %, more preferably no greater than about 5 wt%. Preferred dienes are those that are used for the vulcanization ofethylene/propylene rubbers including, but not limited to, ethylidenenorbornene, vinyl norbornene, dicyclopentadiene, and 1,4-hexadiene.

Embodiments of the invention include high crystallinity polymers havinga heat of fusion, as determined by DSC, with a lower limit of about 60J/g, or 80 J/g. In one embodiment, the high crystallinity polymer has aheat of fusion higher than the heat of fusion of the low crystallinitypolymer.

Embodiments of the invention include high crystallinity polymers havinga melting point with a lower limit of about 70 C, 90 C, 100 C, or 110 C,or 115 C, or 120 C, or 130 C, and can be as high as about 300 C.

In one embodiment, the high crystallinity polymer has a highercrystallinity than the low crystallinity polymer. The degree ofcrystallinity can be determined based on the heat of fusion or densityof the polymer components. In one embodiment, the low crystallinitypolymer has a lower melting point than the high crystallinity polymer,and the additional polymer, if used, has a melting point between that ofthe low crystallinity polymer and that of the high crystallinitypolymer. In another embodiment, the low crystallinity polymer has alower heat of fusion than that of the high crystallinity polymer, andthe additional polymer, if used, has a heat of fusion intermediate ofthe low crystallinity polymer and the high crystallinity polymer.

Compatible Crystallinity

In some embodiments the low crystallinity polymer and high crystallinitypolymer have compatible crystallinity. Compatible crystallinity can beobtained by using polymers for the high crystallinity and lowcrystallinity layers that have the same crystallinity type, i.e., basedon the same crystallizable sequence, such as ethylene sequences orpropylene sequences, or the same stereo-regular sequences, i.e.,isotactic or syndiotactic. For example, compatible crystallinity can beachieved by providing both layers with methylene sequences of sufficientlength, as is achieved by the incorporation of ethylene derived units.

Compatible crystallinity can also be obtained by using polymers withstereo-regular alpha-olefin sequences. This may be achieved, forexample, by providing either syndiotactic sequences or isotacticsequences in both layers.

For purposes of this invention, isotactic refers to a polymer sequencein which greater than 50% of adjacent monomers which have groups ofatoms that are not part of the backbone structure are located either allabove or all below the atoms in the backbone chain, when the latter areall in one plane.

For purposes of this invention, syndiotactic refers to a polymersequence in which greater than 50% of adjacent monomers which havegroups of atoms that are not part of the backbone structure are locatedin a symmetrical fashion above and below the atoms in the backbonechain, when the latter are all in one plane.

Fiber Applications

The polymers, layers, and articles of this invention have many usefulapplications. Representative examples in addition to those that aredescribed elsewhere include mono- and multifilament fibers, staplefibers, binder fibers, spunbond fibers or melt blown fibers (using,e.g., systems as disclosed in U.S. Pat. No. 4,430,563, 4,663,220,4,668,566 or 4,322,027), both woven and nonwoven fabrics, strapping,tape, monofilament, continuous filament (e.g., for use in apparel,upholstery) and structures made from such fibers (including, e.g.,blends of these fibers with other fibers such as PET or cotton. Stapleand filament fibers can be melt spun into the final fiber diameterdirectly without additional drawing, or they can be melt spun into ahigher diameter and subsequently hot or cold drawn to the desireddiameter using conventional fiber drawing techniques.

Crosslinking

Any of the polymers used in any layer of these inventions can be used inessentially the same manner as known polyolefins for the making andusing of elastic fibers. In this regard, the polymers used thisinvention can include functional groups, such as a carbonyl, sulfide,silane radicals, etc., and can be crosslinked or uncrosslinked. Ifcrosslinked, the polymers can be crosslinked using known techniques andmaterials with the understanding that not all crosslinking techniquesand materials are effective on all polyolefins, e.g., while peroxide,azo and electromagnetic radiation (such as e-beam, UV, IR and visiblelight) techniques are all effective to at least a limited extent withpolyethylenes, only some of these, e.g., e-beam, are effective withpolypropylenes and then not necessarily to the same extent as withpolyethylenes. The use of additives, promoters, etc., can be employed asdesired.

“Substantially crosslinked” and similar terms generally mean that thepolymer, shaped or in the form of an article, has xylene extractables ofless than or equal to 70 weight percent (i.e., greater than or equal to30 weight percent gel content), preferably less than or equal to 40weight percent (i.e., greater than or equal to 60 weight percent gelcontent). Xylene extractables (and gel content) are determined inaccordance with ASTM D-2765.

The elastic fibers, layers or polymers used in this invention can becross-linked by any means known in the art, including, but not limitedto, electron-beam irradiation, beta irradiation, gamma irradiation,corona irradiation, silanes, peroxides, allyl compounds and UV radiationwith or without crosslinking catalyst. U.S. patent application Ser. No.10/086,057 (published as US2002/0132923 A1) and U.S. Pat. No. 6,803,014disclose electron-beam irradiation methods that can be used inembodiments of the invention. If crosslinking is to be employed on anarticle. the article is usually shaped before it is cross-linked.

Irradiation may be accomplished by the use of high energy, ionizingelectrons, ultra violet rays, X-rays, gamma rays, beta particles and thelike and combination thereof. Preferably, electrons are employed up to70 megarads dosages. The irradiation source can be any electron beamgenerator operating in a range of about 150 kilovolts to about 6megavolts with a power output capable of supplying the desired dosage.The voltage can be adjusted to appropriate levels which may be, forexample, 100,000, 300,000, 1,000,000 or 2,000,000 or 3,000,000 or6,000,000 or higher or lower. Many other apparati for irradiatingpolymeric materials are known in the art. The irradiation is usuallycarried out at a dosage between about 3 megarads to about 35 megarads,preferably between about 8 to about 20 megarads. Further, theirradiation can be carried out conveniently at room temperature,although higher and lower temperatures, for example 0° C. to about 60°C., may also be employed. Preferably, the irradiation is carried outafter shaping or fabrication of the article. Also, in a preferredembodiment, the ethylene interpolymer which has been incorporated with apro-rad additive is irradiated with electron beam radiation at about 8to about 20 megarads.

Crosslinking can be promoted with a crosslinking catalyst, and anycatalyst that will provide this function can be used. Suitable catalystsgenerally include organic bases, carboxylic acids, and organometalliccompounds including organic titanates and complexes or carboxylates oflead, cobalt, iron, nickel, zinc and tin. Dibutyltindilaurate,dioctyltinmaleate, dibutyltindiacetate, dibutyltindioctoate, stannousacetate, stannous octoate, lead naphthenate, zinc caprylate, cobaltnaphthenate; and the like. Tin carboxylate, especiallydibutyltindilaurate and dioctyltinmaleate, are particularly effectivefor this invention. The catalyst (or mixture of catalysts) is present ina catalytic amount, typically between about 0.015 and about 0.035 phr.

Representative pro-rad additives include, but are not limited to, azocompounds, organic peroxides and polyfunctional vinyl or allyl compoundssuch as, for example, triallyl cyanurate, triallyl isocyanurate,pentaerthritol tetramethacrylate, glutaraldehyde, ethylene glycoldimethacrylate, diallyl maleate, dipropargyl maleate, dipropargylmonoallyl cyanurate, dicumyl peroxide, di-tert-butyl peroxide, t-butylperbenzoate, benzoyl peroxide, cumene hydroperoxide, t-butyl peroctoate,methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di(t-butyl peroxy)hexane,lauryl peroxide, tert-butyl peracetate, azobisisobutyl nitrite and thelike and combination thereof. Preferred pro-rad additives for use in thepresent invention are compounds which have poly-functional (i.e. atleast two) moieties such as C═C, C═N or C═O.

At least one pro-rad additive can be introduced to the ethyleneinterpolymer by any method known in the art. However, preferably thepro-rad additive(s) is introduced via a masterbatch concentratecomprising the same or different base resin as the ethyleneinterpolymer. Preferably, the pro-rad additive concentration for themasterbatch is relatively high e.g., about 25 weight percent (based onthe total weight of the concentrate).

The at least one pro-rad additive is introduced to the ethylene polymerin any effective amount. Preferably, the at least one pro-rad additiveintroduction amount is from about 0.001 to about 5 weight percent, morepreferably from about 0.005 to about 2.5 weight percent and mostpreferably from about 0.015 to about 1 weight percent (based on thetotal weight of the ethylene interpolymer.

In addition to electron-beam irradiation, crosslinking can also beeffected by UV irradiation. U.S. Pat. No. 6,709,742 discloses across-linking method by UV irradiation which can be used in embodimentsof the invention. The method comprises mixing a photoinitiator, with orwithout a photocrosslinker, with a polymer before, during, or after afiber is formed and then exposing the fiber with the photoinitiator tosufficient UV radiation to crosslink the polymer to the desired level.The photoinitiators used in the practice of the invention are aromaticketones, e.g., benzophenones or monoacetals of 1,2-diketones. Theprimary photoreaction of the monacetals is the homolytic cleavage of theα-bond to give acyl and dialkoxyalkyl radicals. This type of α-cleavageis known as a Norrish Type I reaction which is more fully described inW. Horspool and D. Armesto, Organic Photochemistry: A ComprehensiveTreatment, Ellis Horwood Limited, Chichester, England, 1992; J. Kopecky,Organic Photochemistry: A Visual Approach, VCH Publishers, Inc., NewYork, N.Y. 1992; N. J. Turro, et al., Acc. Chem. Res., 1972, 5, 92; andJ. T. Banks, et al., J. Am. Chem. Soc., 1993, 115, 2473. The synthesisof monoacetals of aromatic 1,2 diketones, Ar—CO—C(OR)₂—Ar′ is describedin U.S. Pat. Nos. 4,190,602 and Ger. Offen. 2,337,813. The preferredcompound from this class is 2,2-dimethoxy-2-phenylacetophenone,C₆H₅—CO—C(OCH₃)₂—C₆H₅, which is commercially available from Ciba-Geigyas Irgacure 651. Examples of other aromatic ketones useful in thepractice of this invention as photoinitiators are Irgacure 184, 369,819, 907 and 2959, all available from Ciba-Geigy.

In one embodiment, the photoinitiator is used in combination with aphotocrosslinker. Any photocrosslinker that will upon the generation offree radicals, link two or more polyolefin backbones together throughthe formation of covalent bonds with the backbones can be used in thisinvention. Preferably these photocrosslinkers are polyfunctional, i.e.,they complise two or more sites that upon activation will form acovalent bond with a site on the backbone of the polymer. Representativephotocrosslinkers include, but are not limited to polyfunctional vinylor allyl compounds such as, for example, triallyl cyanurate, triallylisocyanurate, pentaerthritol tetramethacrylate, ethylene glycoldimethacrylate, diallyl maleate, dipropargyl maleate, dipropargylmonoallyl cyanurate and the like. Preferred photocrosslinkers for use inthe present invention are compounds which have polyfunctional (i.e. atleast two) moieties. Particularly preferred photocrosslinkers aretriallycyanurate (TAC) and triallylisocyanurate (TAIC).

Certain compounds act as both a photoinitiator and a photocrosslinker inthe practice of this invention. These compounds are characterized by theability to generate two or more reactive species (e.g., free radicals,carbenes, nitrenes, etc.) upon exposure to UV-light and to subsequentlycovalently bond with two polymer chains. Any compound that can preformthese two functions can be used in the practice of this invention, andrepresentative compounds include the sulfonyl azides described in U.S.Pat. Nos. 6,211,302 and 6,284,842.

In another embodiment, the polymer, layer, or article is subjected tosecondary crosslinking, i.e., crosslinking other than and in addition tophotocrosslinking. In this embodiment, the photoinitiator is used eitherin combination with a nonphotocrosslinker, e.g., a silane, or thepolymer is subjected to a secondary crosslinking procedure, e.g,exposure to E-beam radiation. Representative examples of silanecrosslinkers are described in U.S. Pat. No. 5,824,718, and crosslinkingthrough exposure to E-beam radiation is described in U.S. Pat. Nos.5,525,257 and 5,324,576. The use of a photocrosslinker in thisembodiment is optional.

At least one photoadditive, i.e., photoinitiator and optionalphotocrosslinker, can be introduced to the polymer by any method knownin the alt. However, preferably the photoadditive(s) is (are) introducedvia a masterbatch concentrate comprising the same or different baseresin as the polymer. Preferably, the photoadditive concentration forthe masterbatch is relatively high e.g., about 25 weight percent (basedon the total weight of the concentrate).

The at least one photoadditive is introduced to the polymer in anyeffective amount. Preferably, the at least one photoadditiveintroduction amount is from about 0.001 to about 5, more preferably fromabout 0.005 to about 2.5 and most preferably from about 0.015 to about1, wt % (based on the total weight of the polymer).

The photoinitiator(s) and optional photocrosslinker(s) can be addedduring different stages of the manufacturing process. If photoadditivescan withstand the extrusion temperature, a polyolefin resin can be mixedwith additives before being fed into the extruder, e.g., via amasterbatch addition. Alternatively, additives can be introduced intothe extruder just prior the slot die, but in this case the efficientmixing of components before extrusion is important. In another approach,polyolefin fibers can be drawn without photoadditives, and aphotoinitiator and/or photocrosslinker can be applied to the extrudedfiber via a kiss-roll, spray, dipping into a solution with additives, orby using other industrial methods for post-treatment. The resultingfiber with photoadditive(s) is then cured via electromagnetic radiationin a continuous or batch process. The photo additives can be blendedwith the polyolefin using conventional compounding equipment, includingsingle and twin-screw extruders.

The power of the electromagnetic radiation and the irradiation time arechosen so as to allow efficient crosslinking without polymer degradationand/or dimensional defects. The preferred process is described in EP 0490 854 B1. Photoadditive(s) with sufficient thermal stability is (are)premixed with a polyolefin resin, extruded into a fiber, and irradiatedin a continuous process using one energy source or several units linkedin a series. There are several advantages to using a continuous processcompared with a batch process to cure a fiber or sheet of a knittedfabric which are collected onto a spool.

Irradiation may be accomplished by the use of UV-radiation. Preferably,UV-radiation is employed up to the intensity of 100 J/cm². Theirradiation source can be any UV-light generator operating in a range ofabout 50 watts to about 25000 watts with a power output capable ofsupplying the desired dosage. The wattage can be adjusted to appropriatelevels which may be, for example, 1000 watts or 4800 watts or 6000 wattsor higher or lower. Many other apparati for UV-irradiating polymericmaterials are known in the art. The irradiation is usually carried outat a dosage between about 3 J/cm² to about 500 J/scm², preferablybetween about 5 J/cm² to about 100 J/cm². Further, the irradiation canbe carried out conveniently at room temperature, although higher andlower temperatures, for example 0° C. to about 60° C., may also beemployed. The photocrosslinking process is faster at highertemperatures. Preferably, the irradiation is carried out after shapingor fabrication of the article. In a preferred embodiment, the polymerwhich has been incorporated with a photoadditive is irradiated withUV-radiation at about 10 J/cm² to about 50 j/cm².

Applications of the Article

The articles of the present invention may be used in a variety ofapplications. These include those applications and manufacturingtechniques described in U.S. Pat. No. 5,514,470 and U.S. Pat. No.5,336,545. In one embodiment, the article is a film having at least twolayers, which can be used in diaper back-sheets and similar absorbentgarments such as incontinent garments. In other embodiments, the articleis in the form of a woven or nonwoven fabric, film/fabric laminate orfiber. The fabric may be woven or non-woven. The fiber can be of anysize or shape, and it can be homogeneous or heterogeneous. Ifheterogeneous, then it can be either conjugate, bicomponent orbiconstituent.

The core layer or layers of the film of this invention comprise a lowcrystalline ethylene/alpha-olefin multi-block copolymer. If the film ofthis invention comprises two or more core layers, then the compositionof each core layer can be the same or different from the composition ofthe other core layer(s).

The skin layers of the film of this invention comprise a highcrystalline, preferably non-tacky polyolefin homo- or copolymer. Thecomposition of each skin layer can be the same or different from thecomposition of the other skin layer(s).

Preferably, the particular combination of core and skin layers is chosento insure that the melting point of the skin polymer is not more thanabout 24 C greater, preferably not more than about 20 C greater, thanthe melting point of the core polymer with the lowest melting point.

Ethylene/α-Olefin Multi-Block Interpolymer Component(s)

The articles of the present invention comprise an ethylene/α-olefinmulti-block interpolymer. The ethylene/α-olefin multi-block interpolymermay be contained in the low crystallinity layer, the high crystallinitylayer, or some other part of the article. The ethylene/α-olefinmulti-block interpolymer may be present alone or in a blend with anyother polymer.

The ethylene/α-olefin multi-block interpolymers employed in the presentinvention are a unique class of compounds that are further defined anddiscussed in copending PCT Application No. PCT/US2005/008917, filed onMar. 17, 2005 and published on Sep. 29, 2005 as WO/2005/090427, which inturn claims priority to U.S. Provisional Application No. 60/553,906,filed Mar. 17, 2004. For purposes of United States patent practice, thecontents of the provisional application and the PCT application areherein incorporated by reference in their entirety.

SPECIFIC EMBODIMENTS

Melt Flow Rate (MFR) and Melt Index (MI), as used herein, were measuredby ASTM D-1238 at 23° C. and 190 C, respectively, and both measurementsused weight of 2.16 kg.

Blends of low crystallinity polymer and high crystallinity polymer andother components may be prepared by any procedure that guarantees anintimate mixture of the components. For example, the components can becombined by melt pressing the components together on a Carver press to athickness of about 0.5 millimeter (20 mils) and a temperature of about180 C, rolling up the resulting slab, folding the ends together, andrepeating the pressing, rolling, and folding operation about 10 times.Internal mixers are particularly useful for solution or melt blending.Blending at a temperature of about 180-240 C in a Brabender Plastographfor about 1-20 minutes has been found satisfactory.

Still another method that may be used for admixing the componentsinvolves blending the polymers in a Banbury internal mixer above theflux temperature of all of the components, e.g., about 180 C for about 5minutes. A complete mixture of the polymeric components is indicated bythe uniformity of the morphology of the dispersion of low crystallinitypolymer and high crystallinity polymer. Continuous mixing may also beused. These processes are well known in the art and include single andtwin screw mixing extruders, static mixers for mixing molten polymerstreams of low viscosity, impingement mixers, as well as other machinesand processes, designed to disperse the low crystallinity polymer andthe high crystallinity polymer in intimate contact. Those skilled in theart will be able to determine the appropriate procedure for blending ofthe polymers to balance the need for intimate mixing of the componentingredients with the desire for process economy. Still another methodfor admixing the components of blends using a Haake mixer above the fluxtemperature of all of the components, (e.g. 180° C. and set at 40 rpmrotor speed for about 3-5 minutes until torque reaches steady state).The sample can then be removed and allowed to cool.

Blend components are selected based on the morphology desired for agiven application. The high crystallinity polymer can be co-continuouswith the low crystallinity polymer in the film formed from the blend,however, a dispersed high crystallinity polymer phase in a continuouslow crystallinity polymer phase is preferred. Those skilled in the artcan select the volume fractions of the two components to produce adispersed high crystallinity polymer morphology in a continuous lowcrystallinity polymer matrix based on the viscosity ratio of thecomponents (see S. Wu, Polymer Engineering and Science, Vol. 27, Page335, 1987).

Other Examples of the Invention

The below examples show how the present invention may be implemented.The ratios described in the following examples are in weightpercentages, unless otherwise specified.

Example AA Multi-Layer Pre-Stretched Elastic Films

Layer A—80/20 DOWLEX* 2045 (ethylene/1-octene heterogeneously branchedcopolymer having a melt index of about 1 g/10 min (MI), density of about0.92 g/cc, Tm of about 122° C.)/LDPE 132 (high pressure ethylenehomopolymer having melt index of about 0.22 g/10 min (MI), 0.922 g/cc,Tm of about 108° C.), a blended composition melting peak temperature ofabout 122° C. (DOWLEX* is a trademark of The Dow Chemical Company).

Layer B—Ethylene/1-octene Multi-block copolymer, Overall density ofabout 0.87 g/cc, melt index of about 1 g/10 min., zinc content of about250 ppm (diethyl zinc is used as the chain shuttling agent), meltingpeak temperature of about 115° C. to 125° C., typically about 119-120°C.

Layer C—Same as layer (A).

Layer ratios—5/90/5 or 10/90/10.

The film is made using co-extrusion using a blown film process at a blowup ratio of about 3:1 and a melt temperature of about 450° F., die gapof about 90 mils, to a thickness of about 5 mil. The film ispre-stretched to 400% elongation using set of MDO draw rolls and relaxedto a very low tension to allow substantial elastic recovery beforewinding up on a roll. This pre-stretched elastic film is the inventiveexample. The lower wt % of skin layers are preferred for enhancedelasticity performance of the film.

Example BB Multi-Layer Pre-Stretched Elastic Laminate

Layer A—80/20 DOWLEX 2247 (an ethylene/1-octene copolymer(heterogeneously branched LLDPE) having melt index of about 2.3 g/10min. (MI), density of about 0.917 g/cc, a Tm of about 122° C.)/LDPE 501(high pressure ethylene homopolymer having melt index of about 2 g/10min. (MI), density of about 0.922 g/cc, Tm of about 108° C.), theblended composition having a melting peak temperature of about 122° C.

Layer B—Ethylene/1-octene Multi-block copolymer, Overall density=0.87g/cc, melt index of about 2.5 g/10 min., zinc content of about 250 ppm(diethyl zinc is used as the chain shuttling agent), Melting peaktemperature of about 115° C. to 125° C., typically about 119-120° C.

Layer C—Same as layer (A).

Layer ratios—5/90/5 or 10/90/10.

The film is made using co-extrusion by casting a melt curtain onto aperforated drum and drawing vacuum inside the drum to create holes inthe film. A polypropylene spunbond fabric of about 20 grams/square meterbasis weight point bonded with about 20% of the area bonded. made fromeither Ziegler-Natta or metallocene polypropylene homopolymer orcopolymer, is nipped in to the melt curtain from the other side. Anotherpolypropylene spunbond fabric is adhesively laminated to the film sideto make spunbond/multi-layer film/spunbond laminate. This laminate isthen processed through a ring-rolling process (set of gears) to stretchthe laminate either in machine direction (MD) or cross direction (CD) orboth to a strain necessary for achieving the desired elastic property(typically above about 100% strain). This ring-rolled elastic laminateis then wound up on a roll and is useful as an elastic component forhygiene articles such as diapers.

Example CC Multi-Layer Elastic Laminate

Two polypropylene based spunbond fabric having about 20 grams/squaremeter basis weight, made from either Ziegler-Natta or metallocenepolypropylene homopolymer or copolymer, is pre-stretched in MD to about100 to 150% elongation after pre-heating the spunbond fabric to about 90to 130° C. This results in a “necked” spunbond fabric, being necked inthe CD. An ethylene multi-block copolymer having overall density ofabout 0.87 g/cc, a melt index of about 5 g/10 min., and a zinc level ofabout 250 ppm (diethyl zinc is used as the chain shuttling agent), andmelting peak temperature of about 115° C. to about 125° C. is extrusioncoated at about 2 mil thickness on to this necked spunbond with othernecked spunbond brought into light contact from the other side using anip-roll. This elastic laminate is then cooled and wound up on a roll.This laminate exhibits elastic recovery upon stretching in the CD, andis useful as elastic component of a hygiene article such as a diaper.

Example DD Multi-Layer Elastic Laminate

A row of fibers having a diameter of about 500-1000 denier comprising anethylene multi-block ethylene/1-octene copolymer having overall densityof 0.87 g/cc, melt index of about 10 g/10 min., a zinc level of about250 ppm (diethyl zinc is used as the chain shuttling agent), and meltingpeak temperature of about 115-125° C. is extruded onto a moving belt. Asmall layer (5-10% by weight of the final fibrous composite) of meltblown fabric (nominal fiber diameter of about 10 microns), made fromelastic styrenic block copolymer formulation such asStyrene-ethylene/butene-styrene (SEBS) formulation, is applied to thesefibers on-line. The resultant elastic composite fibrous structure isstretched on-line to about 500% elongation. Polypropylene based spunbondlayers having about 20 grams/square meter basis weight, made from eitherZiegler-Natta or metallocene polypropylene homopolymer or copolymer, arepoint bonded with about 20% of the area bonded on either side of thisstretched fibrous structure using ultrasonic bonding. This stretchedelastic laminate is relaxed to a very low tension to allow substantialrecovery before winding up on a roll. Any suitable thermoplasticelastomer having desired high melt flow rate or melt index could be usedfor the melt blown layer. Such laminates are useful for elasticcomponents of hygiene or medical articles such as side panels oftraining pants.

While the illustrative embodiments of the invention have been describedwith particularity, various other modifications will be apparent to andcan be readily made by those skilled in the art without departing fromthe spirit and scope of the invention. Accordingly, the scope of thefollowing claims are not limited to the examples and descriptions.Rather the claims are to be construed as encompassing all the featuresof patentable novelty that reside in the present invention, includingall features which would be treated as equivalents of these features bythose skilled in the art to which the invention pertains.

When numerical lower limits and numerical upper limits are listed above,ranges from any lower limit to any upper limit are contemplated. Allissued U.S. patents and allowed U.S. patent applications cited above areincorporated herein by reference.

1. An article having at least two layers, the article comprising (a) alow crystallinity layer and (b) a high crystallinity layer, wherein saidarticle is capable of undergoing plastic deformation upon elongation andwherein said article comprises at least one ethylene/α-olefininterpolymer, wherein the ethylene/α-olefin interpolymer is a blockcopolymer comprising at least 50 mole percent ethylene and comprises oneor more of the following criteria: (a) has a Mw/Mn from 1.7 to 3.5, atleast one melting point, Tm, in degrees Celsius, and a density, d, ingrams/cubic centimeter, wherein the numerical values of Tm and dcorrespond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)2; or (b) has a Mw/Mn from 1.7 to 3.5, andis characterized by a heat of fusion, ΔH in J/g, and a delta quantity,ΔT, in degrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar, comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; (e) has a storagemodulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100°C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of1:1 to 9:1; (f) an average block index greater than zero and up to 1.0and a molecular weight distribution, Mw/Mn, greater than 1.3; or (g) atleast one molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has ablock index of at least 0.5 and up to
 1. 2. The article of claim 1,wherein the low crystallinity layer comprises a low crystallinitypolymer and the high crystallinity layer comprises a high crystallinitypolymer.
 3. The article of claim 1, wherein the high crystallinity layercomprises a homopolymer or copolymer of propylene and one or morecomonomers selected from ethylene and C4-C20 alpha-olefins.
 4. Thearticle of claim 1, wherein at least one layer of the article is capableof being elongated in at least one direction to an elongation of atleast 50% of said article's original measurement at a temperature at orbelow the lowest melting point of the polymers comprising the article.5. The article of claim 1, wherein at least one layer of the article hasbeen elongated.
 6. The article of claim 1 in which the low crystallinitypolymer and high crystallinity polymer have a difference incrystallinity of at least 3 weight percent.
 7. The article of claim 1 inwhich the low crystallinity polymer has a melting point as determined byDifferential Scanning Calorimetry (DSC) that is greater than the meltingpoint of the high crystallinity polymer.
 8. The article of claim 1 inwhich at least one high crystallinity layer comprises a nonwoven layer.9. The article of claim 1 in which at least one low crystallinity layercomprises a nonwoven layer.
 10. The article of claim 1 in which at leastone high crystallinity layer comprises a film layer.
 11. The article ofclaim 1 in which at least one high crystallinity layer comprises a filmlayer and at least one low crystallinity layer comprises a film layer.12. The article of claim 1 in which at least one high crystallinitylayer comprises a nonwoven layer and at least one low crystallinitylayer comprises a film layer.
 13. An article comprising a multi-layerfilm comprising (a) a low crystallinity film non-skin layer comprising alow crystallinity polymer and (b) at least two high crystallinity filmlayers, wherein said article is capable of undergoing plasticdeformation upon elongation and wherein said low crystallinity filmlayer comprises at least one ethylene/α-olefin interpolymer, wherein theethylene/α-olefin interpolymer comprises one or more of the followingcriteria: (a) has a Mw/Mn from 1.7 to 3.5, at least one melting point,Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter,wherein the numerical values of Tm and d correspond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)2; or (b) has a Mw/Mn from 1.7 to 3.5, andis characterized by a heat of fusion, ΔH in J/g, and a delta quantity,ΔT, in degrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; (e) has a storagemodulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100°C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of1:1 to 9:1 and wherein at least one high crystallinity layer comprises apolymer selected from the group consisting of a propylene homopolymer, acopolymer of propylene and one or more comonomers selected from ethyleneand C4-C20 alpha-olefins, an ethylene homopolymer, and a copolymer ofethylene and one or more comonomers selected from ethylene and C3-C20alpha-olefins; (f) an average block index greater than zero and up to1.0 and a molecular weight distribution, Mw/Mn, greater than 1.3; or (g)at least one molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has ablock index of at least 0.5 and up to
 1. 14. An article comprising amulti-layer laminate comprising (a) a low crystallinity film or nonwovennon-skin layer comprising a low crystallinity polymer and (b) at leasttwo high crystallinity film or nonwoven layers wherein said article iscapable of undergoing plastic deformation upon elongation and whereinsaid low crystallinity film layer comprises at least oneethylene/α-olefin interpolymer, wherein the ethylene/α-olefininterpolymer comprises one or more of the following criteria: (a) has aMw/Mn from 1.7 to 3.5, at least one melting point, Tm, in degreesCelsius, and a density, d, in grams/cubic centimeter, wherein thenumerical values of Tm and d correspond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)2; or (b) has a Mw/Mn from 1.7 to 3.5, andis characterized by a heat of fusion, ΔH in J/g, and a delta quantity,ΔT, in degrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g.ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; (e) has a storagemodulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100°C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of1:1 to 9′, 1 and wherein said high crystallinity layer(s) comprises apolymer selected from the group consisting of a propylene homopolymer, acopolymer of propylene and one or more comonomers selected from ethyleneand C4-C20 alpha-olefins, an ethylene homopolymer, and a copolymer ofethylene and one or more comonomers selected from ethylene and C3-C20alpha-olefins; (f) an average block index greater than zero and up to1.0 and a molecular weight distribution, Mw/Mn, greater than 1.3; or (g)at least one molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has ablock index of at least 0.5 and up to
 1. 15. The article of claim 14,wherein the high crystallinity film or nonwoven layer(s) comprises apolymer selected from the group consisting of homogeneously branchedpolymers, LLDPE, LDPE, HDPE, SLEP, hPP, and PP plastomers and PPelastomers, and RCP.
 16. The article of claim 14, wherein said lowcrystallinity film layer is a blown film and wherein saidethylene/α-olefin interpolymer has a melt index (ASTM D1238 condition190 C/2.16 kg) of from 0.5 to 5 g/10 minutes.
 17. The article of claim14 in which the multi-layer laminate comprises a third layer locatedbetween the low crystallinity layer and the high crystallinity layer.18. The article of claim 14 in which the multi-layer laminate comprisesa third layer, wherein the low crystallinity layer is located betweenthe third layer and the high crystallinity layer.
 19. The article ofclaim 18, wherein the third layer comprises a second high crystallinitypolymer.
 20. The article of claim 14, wherein the multi-layer laminatehas a haze value of greater than 70%.
 21. The article of claim 14wherein the multi-layer laminate has a permanent set of less than 30%after a 50% hysteresis test.
 22. A garment portion comprising an articleof claim 14 adhered to a garment substrate.
 23. An article of claim 14,wherein the multi-layer film comprises at least one elongated filmlayer.
 24. The article of claim 14 in which at least one film layer iscross-linked.
 25. A fiber comprising (a) a low crystallinity polymer and(b) a high crystallinity polymer, wherein said fiber is capable ofundergoing plastic deformation upon elongation and wherein said lowcrystallinity polymer comprises at least one ethylene/α-olefininterpolymer, wherein the ethylene/α-olefin interpolymer is a blockcopolymer comprising at least 50 mole percent ethylene and comprises atleast one criteria selected from the group consisting of: (a) has aMw/Mn from 1.7 to 3.5, at least one melting point, Tm, in degreesCelsius, and a density, d, in grams/cubic centimeter, wherein thenumerical values of Tm and d correspond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)2; or (b) has a Mw/Mn from 1.7 to 3.5, andis characterized by a heat of fusion, ΔH in J/g, and a delta quantity,ΔT, in degrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elatingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; (e) has a storagemodulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100C), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of1:1 to 9:1 and wherein said high crystallinity polymer comprises apolymer selected from the group consisting of a propylene homopolymer, acopolymer of propylene and one or more comonomers selected from ethyleneand C4-C20 alpha-olefins, an ethylene homopolymer, and a copolymer ofethylene and one or more comonomers selected from ethylene and C3-C20alpha-olefins; (f) an average block index greater than zero and up to1.0 and a molecular weight distribution, Mw/Mn, greater than 1.3; or (g)at least one molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has ablock index of at least 0.5 and up to
 1. 26. The fiber of claim 25,wherein the high crystallinity polymer comprises a polymer selected fromthe group consisting of LLDPE, LDPE, HDPE, SLEP, hPP, and RCP.
 27. Thefiber of claim 25 in the form of a bicomponent fiber in which the highcrystallinity polymer comprises at least a portion of the surface of thefiber.
 28. The fiber of claim 25 in the form of a bicomponent fiber inwhich the low crystallinity polymer comprises at least a portion of thesurface of the fiber.
 29. A web comprising the fiber of claim
 25. 30.The web of claim 29 in which at least a portion of the fibers are bondedto each other.
 31. The fiber of claim 25 in which the high crystallinitypolymer, low Crystallinity polymer, or both, further comprises succinicacid or succinic anhydride functionality.
 32. The fiber of claim 25 inwhich the high crystallinity layer comprises at least one Ziegler-Natta,metallocene or single site catalyzed polyolefin and the lowcrystallinity layer comprises a propylene-based polymer.
 33. An articlecomprising (a) a fiber comprising a low crystallinity polymer and (b) ahigh crystallinity polymer, wherein said article is capable ofundergoing plastic deformation upon elongation and wherein said lowcrystallinity polymer comprises at least one ethylene/α-olefininterpolymer, wherein the ethylene/α-olefin interpolymer comprises atleast one criteria selected from the group consisting of: (a) has aMw/Mn from 1.7 to 3.5, at least one melting point, Tm, in degreesCelsius, and a density, d, in grams/cubic centimeter, wherein thenumerical values of Tm and d correspond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)2; or (b) has a Mw/Mn from 1.7 to 3.5, andis characterized by a heat of fusion, ΔH in J/g, and a delta quantity,ΔT, in degrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; (e) has a storagemodulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100°C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of1:1 to 9:1 and wherein said high crystallinity polymer comprises apolymer selected from the group consisting of a propylene homopolymer, acopolymer of propylene and one or more comonomers selected from ethyleneand C4-C20 alpha-olefins, an ethylene homopolymer, and a copolymer ofethylene and one or more comonomers selected from ethylene and C3-C20alpha-olefins; (f) an average block index greater than zero and up to1.0 and a molecular weight distribution, Mw/Mn, greater than 1.3, or (g)at least one molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has ablock index of at least 0.5 and up to
 1. 34. The article of claim 33further comprising at least one nonwoven layer, wherein said layercomprises high crystallinity polymer (b).
 35. An article comprising: A)a first layer of filaments comprising a low crystallinity polymer; B) asecond layer of elastomeric meltblown fibers, said meltblown fibersbonded to at least a portion of the first layer filaments; C) a thirdlayer of spunbond fibers; and, D) a fourth layer of spunbond fibers;wherein said first and second layers are disposed between said third andfourth layers; wherein the low crystallinity polymer comprises at leastone criteria selected from the group consisting of: (a) has a Mw/Mn from0.7 to 3.5, at least one melting point, Tm, in degrees Celsius, and adensity, d, in grams/cubic centimeter, wherein the numerical values ofTm and d correspond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)2; or (b) has a Mw/Mn from 1.7 to 3.5, andis characterized by a heat of fusion, ΔH in J/g, and a delta quantity,ΔT, in degrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; (e) has a storagemodulus at 25° C., G′(25° C.), and a storage modulus at 100° C., G′(100°C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in the range of1:1 to 9:1; (f) an average block index greater than zero and up to 1.0and a molecular weight distribution, Mw/Mn, greater than 1.3; or (g) atleast one molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has ablock index of at least 0.5 and up to
 1. 36. The article of claim 35,wherein (C) and (D) are skin or surface layers.